Method of manufacture of a paddle type ink jet printer

ABSTRACT

This patent describes a method of manufacturing a paddle type ink jet print head wherein an array of nozzles are formed on a substrate utilizing planar monolithic deposition, lithographic and etching processes. Multiple ink jet heads are formed simultaneously on a single planar substrate such as a silicon wafer. The print heads can be formed utilizing standard VLSI/ULSI processing and can include integrated drive electronics formed on the same substrate. The drive electronics preferably are of a CMOS type. In the final construction, ink can be ejected from the substrate substantially normal to the substrate plane.

CROSS REFERENCES TO RELATED APPLICATIONS

The following co-pending U.S. patent applications, identified by their U.S. patent application Ser. Nos. (USSN), were filed simultaneously to the present application on Jul. 10, 1998, and are hereby incorporated by cross-reference.

    ______________________________________                                         Docket                                                                               Ref-                                                                     No.   erence  Title                                                            ______________________________________                                         IJ01US                                                                               IJ01    Radiant Plunger Ink Jet Printer                                  IJ02US                                                                               IJ02    Electrostatic Ink Jet Printer                                    IJ03US                                                                               IJ03    Planar Thermoelastic Bend Actuator Ink Jet                       IJ04US                                                                               IJ04    Stacked Electrostatic Ink Jet Printer                            IJ05US                                                                               IJ05    Reverse Spring Lever Ink Jet Printer                             IJ06US                                                                               IJ06    Paddle Type Ink Jet Printer                                      IJ07US                                                                               IJ07    Permanent Magnet Electromagnetic Ink Jet Printer                 IJ08US                                                                               IJ08    Planar Swing Grill Electromagnetic Ink Jet Printer               IJ09US                                                                               IJ09    Pump Action Refill Ink Jet Printer                               IJ10US                                                                               IJ10    Pulsed Magnetic Field Ink Jet Printer                            IJ11US                                                                               IJ11    Two Plate Reverse Firing Electromagnetic Ink Jet                               Printer                                                          IJ12US                                                                               IJ12    Linear Stepper Actuator Ink Jet Printer                          IJ13US                                                                               IJ13    Gear Driven Shutter Ink Jet Printer                              IJ14U5                                                                               IJ14    Tapered Magnetic Pole Electromagnetic Ink Jet Printer            IJ15US                                                                               IJ15    Linear Spring Electromagnetic Grill Ink Jet Printer              IJ16US                                                                               IJ16    Lorenz Diaphragm Electromagnetic Ink Jet Printer                 IJ17US                                                                               1117    PTFE Surface Shooting Shuttered Oscillating Pressure                           Ink Jet Printer                                                  IJ18U5                                                                               IJ18    Buckle Grip Oscillating Pressure Ink Jet Printer                 IJ19US                                                                               IJ19    Shutter Based Ink Jet Printer                                    IJ20US                                                                               IJ20    Curling Calyx Thermoelastic Ink Jet Printer                      IJ21US                                                                               IJ21    Thermal Actuated Ink Jet Printer                                 IJ22US                                                                               IJ22    Iris Motion Ink Jet Printer                                      IJ23US                                                                               IJ23    Direct Firing Thermal Bend Actuator Ink Jet Printer              IJ24U5                                                                               IJ24    Conductive PTFE Ben Activator Vented Ink Jet Printer             IJ25U5                                                                               IJ25    Magnetostrictive Ink Jet Printer                                 IJ26US                                                                               IJ26    Shape Memory Alloy Ink Jet Printer                               IJ27U5                                                                               IJ27    Buckle Plate Ink Jet Printer                                     IJ28U5                                                                               IJ28    Thermal Elastic Rotary Impeller Ink Jet Printer                  IJ29US                                                                               IJ29    Thermoelastic Bend Actuator Ink Jet Printer                      IJ30US                                                                               IJ30    Thermoelastic Bend Actuator Using PTFE and                                     Corrugated Copper Ink Jet Printer                                IJ31US                                                                               IJ31    Bend Actuator Direct Ink Supply Ink Jet Printer                  IJ32US                                                                               IJ32    A High Young's Modulus Thermoelastic Ink Jet                                   Printer                                                          IJ33US                                                                               IJ33    Thermally actuated slotted chamber wall ink jet printer          IJ34US                                                                               IJ34    Ink Jet Printer having a thermal actuator comprising an                        external coiled spring                                           IJ35US                                                                               IJ35    Trough Container Ink Jet Printer                                 IJ36US                                                                               IJ36    Dual Chamber Single Vertical Actuator Ink Jet                    IJ37US                                                                               IJ37    Dual Nozzle Single Horizontal Fulcrum Actuator Ink                             Jet                                                              IJ38US                                                                               IJ38    Dual Nozzle Single Horizontal Actuator Ink Jet                   IJ39US                                                                               IJ39    A single bend actuator cupped paddle ink jet printing                          device                                                           IJ40US                                                                               IJ40    A thermally actuated ink jet printer having a series of                        thermal actuator units                                           IJ41US                                                                               IJ41    A thermally actuated ink jet printer including a tapered                       heater element                                                   IJ42US                                                                               IJ42    Radial Back-Curling Thermoelastic Ink Jet                        IJ43US                                                                               IJ43    Inverted Radial Back-Curling Thermoelastic Ink Jet               IJ44US                                                                               IJ44    Surface bend actuator vented ink supply ink jet printer          IJ45U5                                                                               IJ45    Coil Acutuated Magnetic Plate Ink Jet Printer                    ______________________________________                                    

FIELD OF THE INVENTION

The present invention relates to the manufacture of ink jet print heads and, in particular, discloses a method of manufacture of a Paddle Type Ink Jet Printer.

BACKGROUND OF THE INVENTION

Many ink jet printing mechanisms are known. Unfortunately, in mass production techniques, the production of ink jet heads is quite difficult. For example, often, the orifice or nozzle plate is constructed separately from the ink supply and ink ejection mechanism and bonded to the mechanism at a later stage (Hewlett-Packard Journal, Vol. 36 no 5, pp33-37 (1985)). These separate material processing steps required in handling such precision devices often add a substantially expense in manufacturing.

Additionally, side shooting ink jet technologies (U.S. Pat. No. 4,899,181) are often used but again, this limits the amount of mass production throughput given any particular capital investment.

Additionally, more esoteric techniques are also often utilised. These can include electroforming of nickel stage (Hewlett-Packard Journal, Vol. 36 no 5, pp33-37 (1985)), electro-discharge machining, laser ablation (U.S. Pat. No. 5,208,604), micro-punching, etc.

The utilisation of the above techniques is likely to add substantial expense to the mass production of ink jet print heads and therefore add substantially to their final cost.

It would therefore be desirable if an efficient system for the mass production of ink jet print heads could be developed.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a method for the creation of a paddle type ink jet printer.

In accordance with a first aspect of the present invention, there is provided a method of manufacturing a paddle type ink jet print head wherein an array of nozzles are formed on a substrate utilising planar monolithic deposition, lithographic and etching processes. Preferably, multiple ink jet heads are formed simultaneously on a single planar substrate such as a silicon wafer.

The print heads can be formed utilising standard vlsi/ulsi processing and can include integrated drive electronics formed on the same substrate. The drive electronics preferably are of a CMOS type. In the final construction, ink can be ejected from the substrate substantially normal to the substrate.

In accordance with a further aspect of the present invention, there is provided a method of manufacture of an ink jet print head arrangement including a series of nozzle chambers, the method comprising the steps of: (a) utilizing an initial semiconductor wafer having an electrical circuitry layer and a buried epitaxial layer formed thereon, in addition to a top protecting layer having a series of vias interconnected to predetermined portions of the circuitry layer; (b) forming on the semiconductor wafer layer a first conductive layer including a first conductive coil interconnected to predetermined portions of the circuitry layer; (c) depositing and etching, on the first conductive layer, a non-conductive layer including predetermined vias for the interconnection of subsequent layers with lower layers; (d) forming a second conductive layer on the nonconducting layer, including a second conductive coil and the interconnection of predetermined portions of the coil with the first conductive coil and the circuitry layer; (e) depositing and etching a second non-conductive layer over the second conductive layer the etching including etching a series of slots in the second non-conductive layer; (f) etching a series of slots through the first and second non-conductive layers, the first and second conductive layers so as to define a nozzle paddle; (g) etching the semiconductor wafer under the nozzle paddle so as to define a nozzle chamber; (h) back etching the semiconductor wafer to the epitaxial layer; and (i) etching the epitaxial layer to define a nozzle ejection hole therein interconnecting with the nozzle chamber;

The step (g) can comprise a crystallographic etch and can utilize the epitaxial layer as an etch stop.

The step (i) preferably can include etching a series of small holes in a wall of the nozzle chamber interconnecting the chamber with the ambient atmosphere.

The first conductive layer and the second conductive layer are preferably formed from substantially copper.

The steps are preferably also utilized to simultaneously separate the wafer into separate printheads.

BRIEF DESCRIPTION OF THE DRAWINGS

Notwithstanding any other forms which may fall within the scope of the present invention, preferred forms of the invention will now be described, by way of example only, with reference to the accompanying drawings which:

FIG. 1 is a cross-sectional view of a single ink jet nozzle constructed in accordance with the preferred embodiment in its quiescent state;

FIG. 2 is a cross-sectional view of a single ink jet nozzle constructed in accordance with the preferred embodiment, illustrating the state upon activation of the actuator;

FIG. 3 is an exploded perspective view illustrating the construction of a single ink jet nozzle in accordance with the preferred embodiment;

FIG. 4 provides a legend of the materials indicated in FIGS. 5 to 15; and

FIG. 5 to FIG. 15 illustrate sectional views of the manufacturing steps in one form of construction of an ink jet printhead nozzle.

DESCRIPTION OF PREFERRED AND OTHER EMBODIMENTS

Referring now to FIG. 1, there is illustrated a cross-sectional view of a single ink nozzle unit 10 constructed in accordance with the preferred embodiment. The ink nozzle unit 10 includes an ink ejection nozzle 11 for the ejection of ink which resides in a nozzle chamber 13. The ink is ejected from the nozzle chamber 13 by means of movement of paddle 15. The paddle 15 operates in a magnetic field 16 which runs along the plane of the paddle 15. The paddle 15 includes at least one solenoid coil 17 which operates under the control of nozzle activation signal. The paddle 15 operates in accordance with the well known principal of the force experienced by a moving electric charge in a magnetic field. Hence, when it is desired to activate the paddle 15 to eject an ink drop out of ink ejection nozzle 11, the solenoid coil 17 is activated. As a result of the activation, one end of the paddle will experience a downward force 19 while the other end of the paddle will experience an upward force 20. The downward force 19 results in a corresponding movement of the paddle and the resultant ejection of ink.

As can be seen from the cross section of FIG. 1, the paddle 15 can comprise multiple layers of solenoid wires with the solenoid wires, e.g. 21, forming a complete circuit having the current flow in a counter clockwise direction around a centre of the paddle 15. This results in paddle 15 experiencing a rotation about an axis through (as illustrated in FIG. 2) the centre point the rotation being assisted by means of a torsional spring, e.g. 22, which acts to return the paddle 15 to its quiescent state after deactivation of the current paddle 15. Whilst a torsional spring 22 is to be preferred it is envisaged that other forms of springs may be possible such as a leaf spring or the like.

The nozzle chamber 13 refills due to the surface tension of the ink at the ejection nozzle 11 after the ejection of ink.

Manufacturing Construction Process

The construction of the ink jet nozzles can proceed by way of utilisation of microelectronic fabrication techniques commonly known to those skilled in the field of semi-conductor fabrication. For a general introduction to a micro-electro mechanical system (MEMS) reference is made to standard proceedings in this field including the proceedings of the SPIE (International Society for Optical Engineering), volumes 2642 and 2882 which contain the proceedings for recent advances and conferences in this field.

In accordance with one form of construction, two wafers are utilized upon which the active circuitry and ink jet print nozzles are fabricated and a further wafer in which the ink channels are fabricated.

Turning now to FIG. 3, there is illustrated an exploded perspective view of a single ink jet nozzle constructed in accordance with the preferred embodiment. Construction begins which a silicon wafer 40 upon which has been fabricated an epitaxial boron doped layer 41 and an epitaxial silicon layer 42. The boron layer is doped to a concentration of preferably 10²⁰ /cm³ of boron or more and is approximately 2 microns thick. The silicon epitaxial layer is constructed to be approximately 8 microns thick and is doped in a manner suitable for the active semi conductor device technology.

Next, the drive transistors and distribution circuitry are constructed in accordance with the fabrication process chosen resulting in a CMOS logic and drive transistor level 43. A silicon nitride layer 44 is then deposited.

The paddle metal layers are constructed utilizing a damascene process which is a well known process utilizing chemical mechanical polishing techniques (CMP) well known for utilization as a multi-level metal application. The solenoid coils in paddle 15 (FIG. 1) can be constructed from a double layer which for a first layer 45, is produced utilising a single damascene process.

Next, a second layer 46 is deposited utilizing this time a dual damascene process. The copper layers 45, 46 include contact posts 47, 48, for interconnection of the electromagnetic coil to the CMOS layer 43 through vias in the silicon nitride layer 44 (not shown). However, the metal post portion also includes a via interconnecting it with the lower copper level. The damascene process is finished with a planarised glass layer. The glass layers produced during utilisation of the damascene processes utilised for the deposition of layers 45, 46, are shown as one layer 75 in FIG. 3.

Subsequently, the paddle is formed and separated from the adjacent glass layer by means of a plasma edge as the edge being down to the position of stop layer 80. Further, the nozzle chamber 13 underneath the panel is removed by means of a silicon anisotropic wet edge which will edge down to the boron layer 41. A passivation layer is then applied. The passivation layer can comprise a conformable diamond like carbon layer or a high density Si₃ N₄ coating, this coating provides a protective layer for the paddle and its surrounds as the paddle must exist in the highly corrosive environment of water and ink.

Next, the silicon wafer can be back-etched through the boron doped layer and the ejection port 11 and an ejection port rim 50 (FIG. 1) can also be formed utilising etching procedures. One form of alternative detailed manufacturing process which can be used to fabricate monolithic ink jet print heads operating in accordance with the principles taught by the present embodiment can proceed utilizing the following steps:

1. Using a double sided polished wafer deposit 3 microns of epitaxial silicon heavily doped with boron.

2. Deposit 10 microns of epitaxial silicon, either p-type or n-type, depending upon the CMOS process used.

3. Complete a 0.5 micron, one poly, 2 metal CMOS process. This step is shown in FIG. 5. For clarity, these diagrams may not be to scale, and may not represent a cross section though any single plane of the nozzle. FIG. 4 is a key to representations of various materials in these manufacturing diagrams, and those of other cross referenced ink jet configurations.

4. Deposit 0.1 microns of silicon nitride (Si3N4).

5. Etch the nitride layer using Mask 1. This mask defines the contact vias from the solenoid coil to the second-level metal contacts.

6. Deposit a seed layer of copper. Copper is used for its low resistivity (which results in higher efficiency) and its high electromigration resistance, which increases reliability at high current densities.

7. Spin on 3 microns of resist, expose with Mask 2, and develop. This mask defines the first level coil of the solenoid. The resist acts as an electroplating mold. This step is shown in FIG. 6.

8. Electroplate 2 microns of copper.

9. Strip the resist and etch the exposed copper seed layer. This step is shown in FIG. 7.

10. Deposit 0.1 microns of silicon nitride (Si3N4).

11. Etch the nitride layer using Mask 3. This mask defines the contact vias between the first level and the second level of the solenoid.

12. Deposit a seed layer of copper.

13. Spin on 3 microns of resist, expose with Mask 4, and develop. This mask defines the second level coil of the solenoid. The resist acts as an electroplating mold. This step is shown in FIG. 8.

14. Electroplate 2 microns of copper.

15. Strip the resist and etch the exposed copper seed layer. This step is shown in FIG. 9.

16. Wafer probe. All electrical connections are complete at this point, bond pads are accessible, and the chips are not yet separated.

17. Deposit 0.1 microns of silicon nitride.

18. Etch the nitride and CMOS oxide layers down to silicon using Mask 5. This mask defines the nozzle chamber mask and the edges of the print heads chips for crystallographic wet etching. This step is shown in FIG. 10.

19. Crystallographically etch the exposed silicon using KOH. This etch stops on <111> crystallographic planes, and on the boron doped silicon buried layer. Due to the design of Mask 5, this etch undercuts the silicon, providing clearance for the paddle to rotate downwards.

20. Mount the wafer on a glass blank and back-etch the wafer using KOH, with no mask. This etch thins the wafer and stops at the buried boron doped silicon layer. This step is shown in FIG. 11.

21. Plasma back-etch the boron doped silicon layer to a depth of 1 micron using Mask 6. This mask defines the nozzle rim. This step is shown in FIG. 12.

22. Plasma back-etch through the boron doped layer using Mask 7. This mask defines the nozzle, and the edge of the chips. At this stage, the chips are separate, but are still mounted on the glass blank. This step is shown in FIG. 13.

23. Strip the adhesive layer to detach the chips from the glass blank. This step is shown in FIG. 14.

24. Mount the print heads in their packaging, which may be a molded plastic former incorporating ink channels which supply different colors of ink to the appropriate regions of the front surface of the wafer.

25. Connect the print heads to their interconnect systems.

26. Hydrophobize the front surface of the print heads.

27. Fill with ink, apply a strong magnetic field in the plane of the chip surface, and test the completed print heads. A filled nozzle is shown in FIG. 15.

It can be seen from the foregoing description that the preferred embodiment comprises a new form of ink ejection device having advantages over the aforementioned ink jet printers. Further, there has been described one form of construction of such an ink jet device although it would be obvious to those skilled in the art that many alternative constructions are possible. The construction of the panel type ink jet printer is varied in accordance with those complex variable decisions made in the construction of integrated circuit type devices.

It would be appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention as shown in the specific embodiment without departing from the spirit or scope of the invention as broadly described. The present embodiment is, therefore, to be considered in all respects to be illustrative and not restrictive.

Ink Jet Technologies

The embodiments of the invention use an ink jet printer type device. Of course many different devices could be used. However presently popular ink jet printing technologies are unlikely to be suitable.

The most significant problem with thermal ink jet is power consumption. This is approximately 100 times that required for high speed, and stems from the energy-inefficient means of drop ejection. This involves the rapid boiling of water to produce a vapor bubble which expels the ink. Water has a very high heat capacity, and must be superheated in thermal ink jet applications. This leads to an efficiency of around 0.02%, from electricity input to drop momentum (and increased surface area) out.

The most significant problem with piezoelectric ink jet is size and cost. Piezoelectric crystals have a very small deflection at reasonable drive voltages, and therefore require a large area for each nozzle. Also, each piezoelectric actuator must be connected to its drive circuit on a separate substrate. This is not a significant problem at the current limit of around 300 nozzles per print head, but is a major impediment to the fabrication of pagewidth print heads with 19,200 nozzles.

Ideally, the ink jet technologies used meet the stringent requirements of in-camera digital color printing and other high quality, high speed, low cost printing applications. To meet the requirements of digital photography, new ink jet technologies have been created. The target features include:

low power (less than 10 Watts)

high resolution capability (1,600 dpi or more)

photographic quality output

low manufacturing cost

small size (pagewidth times minimum cross section)

high speed (<2 seconds per page).

All of these features can be met or exceeded by the ink jet systems described below with differing levels of difficulty. Forty-five different ink jet technologies have been developed by the Assignee to give a wide range of choices for high volume manufacture. These technologies form part of separate applications assigned to the present Assignee as set out in the table below.

The ink jet designs shown here are suitable for a wide range of digital printing systems, from battery powered one-time use digital cameras, through to desktop and network printers, and through to commercial printing systems

For ease of manufacture using standard process equipment, the print head is designed to be a monolithic 0.5 micron CMOS chip with MEMS post processing. For color photographic applications, the print head is 100 mm long, with a width which depends upon the ink jet type. The smallest print head designed is IJ38, which is 0.35 mm wide, giving a chip area of 35 square mm. The print heads each contain 19,200 nozzles plus data and control circuitry.

Ink is supplied to the back of the print head by injection molded plastic ink channels. The molding requires 50 micron features, which can be created using a lithographically micromachined insert in a standard injection molding tool. Ink flows through holes etched through the wafer to the nozzle chambers fabricated on the front surface of the wafer. The print head is connected to the camera circuitry by tape automated bonding.

Tables of Drop-on-Demand Ink Jets

The present invention is useful in the field of digital printing, in particular, ink jet printing. A number of patent applications in this field were filed simultaneously and incorporated by cross reference.

Eleven important characteristics of the fundamental operation of individual ink jet nozzles have been identified. These characteristics are largely orthogonal, and so can be elucidated as an eleven dimensional matrix. Most of the eleven axes of this matrix include entries developed by the present assignee.

The following tables form the axes of an eleven dimensional table of ink jet types.

Actuator mechanism (18 types)

Basic operation mode (7 types)

Auxiliary mechanism (8 types)

Actuator amplification or modification method (17 types)

Actuator motion (19 types)

Nozzle refill method (4 types)

Method of restricting back-flow through inlet (10 types)

Nozzle clearing method (9 types)

Nozzle plate construction (9 types)

Drop ejection direction (5 types)

Ink type (7 types)

The complete eleven dimensional table represented by these axes contains 36.9 billion possible configurations of ink jet nozzle. While not all of the possible combinations result in a viable ink jet technology, many million configurations are viable. It is clearly impractical to elucidate all of the possible configurations. Instead, certain ink jet types have been investigated in detail. These are designated IJ01 to IJ45 which matches the docket numbers in the table under the heading CROSS REFERENCES TO RELATED APPLICATIONS.

Other ink jet configurations can readily be derived from these 45 examples by substituting alternative configurations along one or more of the 11 axes. Most of the IJ01 to IJ45 examples can be made into ink jet print heads with characteristics superior to any currently available ink jet technology.

Where there are prior art examples known to the inventor, one or more of these examples are listed in the examples column of the tables below. The IJ01 to IJ45 series are also listed in the examples column. In some cases, a printer may be listed more than once in a table, where it shares characteristics with more than one entry.

Suitable applications include: Home printers, Office network printers, Short run digital printers, Commercial print systems, Fabric printers, Pocket printers, Internet WWW printers, Video printers, Medical imaging, Wide format printers, Notebook PC printers, Fax machines, Industrial printing systems, Photocopiers, Photographic minilabs etc.

The information associated with the aforementioned 11 dimensional matrix are set out in the following tables.

    __________________________________________________________________________     ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS)                        Actuator                                                                       Mechanism                                                                            Description     Advantages    Disadvantages     Examples                 __________________________________________________________________________     Thermal                                                                              An electrothermal heater heats the                                                             ♦ Large force generated                                                        ♦ High                                                                             ♦                                                                Canon Bubblejet          bubble                                                                               ink to above boiling point,                                                                    ♦ Simple construction                                                          ♦ Ink carrier limited                                            to water          1979 Endo et al GB             transferring significant heat to the                                                           ♦ No moving parts                                                              ♦ Low                                                                              patent 2,007,162               aqueous ink. A bubble nucleates and                                                            ♦ Fast operation                                                               ♦ High temperatures                                              required          ♦                                                                Xerox heater-in-               quickly forms, expelling the ink.                                                              ♦ Small chip area required                                                     ♦ High mechanical                                                stress            pit 1990 Hawkins                                                               et                             The efficiency of the process is low,                                                          actuator      ♦ Unusual materials                                              required          al U.S. Pat. No.               with typically less than 0.05% of the                                                                        ♦ Large drive                                                    transistors       4,899,181                      electrical energy being transformed                                                                          ♦ Cavitation causes                                              actuator failure  ♦                                                                Hewlett-Packard                into kinetic energy of the drop.                                                                             ♦ Kogation reduces                                               bubble formation  TIJ 1982 Vaught et                                           ♦ Large print heads are                                          difficult to      al U.S. Pat. No.                                             fabricate         4,490,728                Piezoelectric                                                                        A piezoelectric crystal such as lead                                                           ♦ Low power consumption                                                        ♦ Very large area                                                required for actuator                                                                            ♦                                                                Kyser et al U.S.               lanthanum zirconate (PZT) is                                                                   ♦ Many ink types can be                                                        ♦ Difficult to                                                   integrate with electronics                                                                       Pat. No. 3,946,398             electrically activated, and either                                                             ♦ Fast operation                                                               ♦ High voltage drive                                             transistors required                                                                             ♦                                                                Zoltan U.S.                    expands, shears, or bends to apply                                                             ♦ High efficiency                                                              ♦ Full pagewidth print                                           heads impractical Pat. No. 3,683,212             pressure to the ink, ejecting drops.                                                                         due to actuator size                                                                             ♦                                                                1973 Stemme                                                  ♦ Requires electrical                                            poling in high field                                                                             U.S. Pat. No.                                                strengths during manufacture                                                                     3,747,120                                                                      ♦                                                                Epson Stylus                                                                   ♦                                                                Tektronix                                                                      ♦                                                                IJ04                     Electro-                                                                             An electric field is used to activate                                                          ♦ Low power consumption                                                        ♦ Low maximum strain                                             (approx. 0.01%)   ♦                                                                Seiko Epson,             strictive                                                                            electrostriction in relaxor materials                                                          ♦ Many ink types can be                                                        ♦ Large area required                                            for actuator due to                                                                              Usui et all JP                 such as lead lanthanum zirconate                                                               ♦ Low thermal expansion                                                        low strain        253401/96                      titanate (PLZT) or lead magnesium                                                              ♦ Electric field strength                                                      ♦ Response speed is                                              marginal (˜10                                                                              ♦                                                                IJ04                           niobate (PMN).  required (approx. 3.5 V/μm)                                                               ♦ High voltage drive                                             transistors required                                             can be generated without                                                                     ♦ Full pagewidth print                                           heads impractical                                                difficulty    due to actuator size                                             ♦ Does not require electrical                                    poling                                                   Ferroelectric                                                                        An electric field is used to induce a                                                          ♦ Low power consumption                                                        ♦ Difficult to                                                   integrate with electronics                                                                       ♦                                                                IJ04                           phase transition between the                                                                   ♦ Many ink types can be                                                        ♦ Unusual materials                                              such as PLZSnT are                               antiferroelectric (AFE) and                                                                    ♦ Fast operation (<1                                                           required                                         ferroelectric (FE) phase. Perovskite                                                           ♦ Relatively high longitudinal                                                 ♦ Actuators require a                                            large area                                       materials such as tin modified lead                                                            strain                                                         lanthanum zirconate titanate                                                                   ♦ High efficiency                                (PLZSnT) exhibit large strains of up                                                           ♦ Electric field strength of                     to 1% associated with the AFE to FE                                                            around 3 V/μm can be                                        phase transition.                                                                              readily provided                                         Electrostatic                                                                        Conductive plates are separated by a                                                           ♦ Low power consumption                                                        ♦ Difficult to operate                                           electrostatic     ♦                                                                IJ02, IJ04               plates                                                                               compressible or fluid dielectric                                                               ♦ Many ink types can be                                                        devices in an aqueous environment                (usually air). Upon application of a                                                           ♦ Fast operation                                                               ♦ The electrostatic                                              actuator will normally                           voltage, the plates attract each other                                                                       need to be separated from the ink                and displace ink, causing drop                                                                               ♦ Very large area                                                required to achieve                              ejection. The conductive plates may                                                                          high forces                                      be in a comb or honeycomb     ♦ High voltage drive                                             transistors may be                               structure, or stacked to increase the                                                                        required                                         surface area and therefore the force.                                                                        ♦ Full pagewidth print                                           heads are not                                                                  competitive due to actuator size           Electrostatic                                                                        A strong electric field is applied to                                                          ♦ Low current consumption                                                      ♦ High voltage                                                                     ♦                                                                1989 Saito et al,        pull on ink                                                                          the ink, whereupon electrostatic                                                               ♦ Low temperature                                                              ♦ May be damaged by                                              sparks due to air U.S. Pat. No.                  attraction accelerates the ink towards                                                                       breakdown         4,799,068                      the print medium.             ♦ Required field                                                 strength increases as                                                                            ♦                                                                1989 Miura et al,                                            drop size decreases                                                                              U.S. Pat. No.                                                ♦ High voltage drive                                             transistors required                                                                             4,810,954                                                    ♦ Electrostatic field                                            attracts dust     ♦                                                                Tone-jet                 Permanent                                                                            An electromagnet directly attracts a                                                           ♦ Low power consumption                                                        ♦ Complex                                                                          ♦                                                                IJ07, IJ10               magnet                                                                               permanent magnet, displacing ink                                                               ♦ Many ink types can be                                                        ♦ Permanent magnetic                                             material such as                           electro-                                                                             and causing drop ejection. Rare earth                                                          ♦ Fast operation                                                               Neodymium Iron Boron(NdFeB)                magnetic                                                                             magnets with a field strength around                                                           ♦ High efficiency                                                              required.                                        1 Tesla can be used. Examples are:                                                             ♦ Easy extension from                                                          ♦ High local currents                                            required                                         Samarium Cobalt (SaCo) and                                                                     nozzles to pagewidth print                                                                   ♦ Copper metalization                                            should be used for                               magnetic materials in the                                                                      heads         long electromigration lifetime and                                             low                                              neodymium iron boron family   resistivity                                      (NdFeB, NdDyFeBNb, NdDyFeB,   ♦ Pigmented inks are                                             usually infeasible                               etc)                          ♦ Operating temperature                                          limited to the                                                                 Curie temperature (around 540 K.)          Soft  A solenoid induced a magnetic field                                                            ♦ Low power consumption                                                        ♦ Complex                                                                          ♦                                                                IJ01, IJ05, IJ08,        magnetic                                                                             in a soft magnetic core or yoke                                                                ♦ Many ink types can be                                                        ♦ Materials not usually                                          present in a      IJ10                     core electro-                                                                        fabricated from a ferrous material                                                             ♦ Fast operation                                                               CMOS fab such as NiFe, CoNiFe,                                                                   ♦                                                                IJ12, IJ14, IJ15,        magnetic                                                                             such as electroplated iron alloys such                                                         ♦ High efficiency                                                              CoFe are required IJ17                           as CoNiFe [1], CoFe, or NiFe alloys.                                                           ♦ Easy extension from                                                          ♦ High local currents                                            required                                         Typically, the soft magnetic material                                                          nozzles to pagewidth print                                                                   ♦ Copper metalization                                            should be used for                               is in two parts, which are normally                                                            heads         long electromigration lifetime and                                             low                                              held apart by a spring. When the                                                                             resistivity                                      solenoid is actuated, the two parts                                                                          ♦ Electroplating is                                              required                                         attract, displacing the ink.  ♦ High saturation flux                                           density is required                                                            (2.0-2.1 T is achievable with CoNiFe                                           [1])                                       Magnetic                                                                             The Lorenz force acting on a current                                                           ♦ Low power consumption                                                        ♦ Force acts as a                                                twisting motion   ♦                                                                IJ06, IJ11, IJ13,        Lorenz force                                                                         carrying wire in a magnetic field is                                                           ♦ Many ink types can be                                                        ♦ Typically, only a                                              quarter of the    IJ16                           utilized.       ♦ Fast operation                                                               solenoid length provides force in a              This allows the magnetic field to be                                                           ♦ High efficiency                                                              useful direction                                 supplied externally to the print head,                                                         ♦ Easy extension from                                                          ♦ High local currents                                            required                                         for example with rare earth                                                                    nozzles to pagewidth print                                                                   ♦ Copper metalization                                            should be used for                               permanent magnets.                                                                             heads         long electromigration lifetime and                                             low                                              Only the current carrying wire need                                                                          resistivity                                      be fabricated on the print-head,                                                                             ♦ Pigmented inks are                                             usually infeasible                               simplifying materials requirements.                                      Magneto-                                                                             The actuator uses the giant                                                                    ♦ Many ink types can be                                                        ♦ Force acts as a                                                twisting motion   ♦                                                                Fischenbeck,             striction                                                                            magnetostrictive effect of materials                                                           ♦ Fast operation                                                               ♦ Unusual materials                                              such as Terfenol-D                                                                               U.S. Pat. No.                  such as Terfenol-D (an alloy of                                                                ♦ Fasy extension from                                                          are required      4,032,929                      terbium, dysprosium and iron                                                                   nozzles to pagewidth print                                                                   ♦ High local currents                                            required          ♦                                                                IJ25                           developed at the Naval Ordnance                                                                heads         ♦ Copper metalization                                            should be used for                               Laboratory, hence Ter-Fe-NOL). For                                                             ♦ High force is available                                                      long electromigration lifetime and                                             low                                              best efficiency, the actuator should                                                                         resistivity                                      be pre-stressed to approx. 8 MPa.                                                                            ♦ Pre-stressing may be                                           required                                   Surface                                                                              Ink under positive pressure is held in                                                         ♦ Low power consumption                                                        ♦ Requires                                                       supplementary force to                                                                           ♦                                                                Silverbrook, EP          tension                                                                              a nozzle by surface tension. The                                                               ♦ Simple construction                                                          drop separation   0771 658 A2 and          reduction                                                                            surface tension of the ink is reduced                                                          ♦ No unusual materials                                                         ♦ Requires special ink                                           surfactants       related patent                 below the bubble threshold, causing                                                            required in fabrication                                                                      ♦ Speed may be limited                                           by surfactant     applications                   the ink to egress from the nozzle.                                                             ♦ High efficiency                                                              properties                                                       ♦ Easy extension from single                                     nozzles to pagewidth print                                                     heads                                                    Viscosity                                                                            The ink viscosity is locally reduced                                                           ♦ Simple construction                                                          ♦ Requires                                                       supplementary force to                                                                           ♦                                                                Silverbrook, EP          reduction                                                                            to select which drops are to be                                                                ♦ No unusual materials                                                         drop separation   0771 658 A2 and                ejected. A viscosity reduction can be                                                          required in fabrication                                                                      ♦ Requires special ink                                           viscosity         related patent                 achieved electrothermally with most                                                            ♦ Easy extension from                                                          properties        applications                   inks, but special inks can be                                                                  nozzles to pagewidth print                                                                   ♦ High speed is                                                  difficult to achieve                             engineered for a 100:1 viscosity                                                               heads         ♦ Requires oscillating                                           ink, pressure                                    reduction.                    ♦ A high temperature                                             difference                                                                     (typically 80 degrees) is required         Acoustic                                                                             An acoustic wave is generated and                                                              ♦ Can operate without                                                          ♦ Complex drive                                                  circuitry         ♦                                                                1993 Hadimioglu                focussed upon the drop ejection                                                                nozzle plate  ♦ Complex                                                                          et al, EUP 550,192             region.                       ♦ Low                                                                              ♦                                                                1993 Elrod et al,                                            ♦ Poor control of drop                                           position          EUP 572,220                                                  ♦ Poor control of drop                                           volume                                     Thermo-                                                                              An actuator which relies upon                                                                  ♦ Low power consumption                                                        ♦ Efficient aqueous                                              operation requires a                                                                             ♦                                                                IJ03, IJ09, IJ17,        elastic                                                                              differential thermal expansion upon                                                            ♦ Many ink types can be                                                        thermal insulator on the hot                                                                     IJ18                     bend  Joule heating is used.                                                                         ♦ Simple planar fabrication                                                    ♦ Corrosion prevention                                           can be difficult  ♦                                                                IJ19, IJ20, IJ21,        actuator              ♦ Small chip area required                                                     ♦ Pigmented inks may be                                          infeasible, as    IJ22                                           each actuator pigment particles may jam the                                                                    ♦                                                                IJ23, IJ24, IJ27,                              ♦ Fast operation                                                               actuator          IJ28                                           ♦ High efficiency ♦                                                                IJ29, IJ30, IJ31,                              ♦ CMOS compatible voltages                                                                       IJ32                                           and currents                    ♦                                                                IJ33, IJ34, IJ35,                              ♦ Standard MEMS processes                                                                        IJ36                                           can be used                     ♦                                                                IJ37, IJ38 ,IJ39,                              ♦ Easy extension from                                                                            IJ40le                                         nozzles to pagewidth print      ♦                                                                IJ41                                           heads                                                    High CTE                                                                             A material with a very high                                                                    ♦ High force can be                                                            ♦ Requires special                                               material (e.g. PTFE)                                                                             ♦                                                                IJ09, IJ17, IJ18,        thermo-                                                                              coefficient of thermal expansion                                                               ♦ PTFE is a candidate for                                                      ♦ Requires a PTFE                                                deposition process,                                                                              IJ20                     elastic                                                                              (CTE) such as   dielectric constant                                                                          which is not yet standard in ULSI                                              fabs              ♦                                                                IJ21, IJ22, IJ23,        actuator                                                                             polytetrafluoroethylene (PTFE) is                                                              insulation in ULSI                                                                           ♦ PTFE deposition                                                cannot be followed                                                                               IJ24                           used. As high CTE materials are                                                                ♦ Very low power                                                               with high temperature (above                                                   350° C.)   ♦                                                                IJ27, IJ28, IJ29,              usually non-conductive, a heater                                                               consumption   processing        IJ30                           fabricated from a conductive                                                                   ♦ Many ink types can be                                                        ♦ Pigmented inks may be                                          infeasible, as    ♦                                                                IJ31, IJ42, IJ43,              material is incorporated. A 50 μm                                                           ♦ Simple planar fabrication                                                    pigment particles may jam the                                                                    IJ44                           long PTFE bend actuator with                                                                   ♦ Small chip area required                                                     actuator                                         polysilicon heater and 15 mW power                                                             each actuator                                                  input can provide 180 μN force and                                                          ♦ Fast operation                                 10 μm deflection. Actuator motions                                                          ♦ High efficiency                                include:        ♦ CMOS compatible voltages                       1) Bend         and currents                                                   2) Push         ♦ Easy extension from single                     3) Buckle       nozzles to pagewidth print                                     4) Rotate       heads                                                    Conductive                                                                           A polymer with a high coefficient of                                                           ♦ High force can be                                                            ♦ Requires special                                               materials         ♦                                                                IJ24                     polymer                                                                              thermal expansion (such as PTFE) is                                                            ♦ Very low power                                                               development (High CTE conductive           thermo-                                                                              doped with conducting substances to                                                            consumption   polymer)                                   elastic                                                                              increase its conductivity to about 3                                                           ♦ Many ink types can be                                                        ♦ Requires a PTFE                                                deposition process,                        actuator                                                                             orders of magnitude below that of                                                              ♦ Simple planar fabrication                                                    which is not yet standard in ULSI                                              fabs                                             copper. The conducting polymer                                                                 ♦ Small chip area required                                                     ♦ PTFE deposition                                                cannot be followed                               expands when resistively heated.                                                               each actuator with high temperature (above                                                   350° C.)                                  Examples of conducting dopants                                                                 ♦ Fast operation                                                               processing                                       include:        ♦ High efficiency                                                              ♦ Evaporation and CVD                                            deposition                                       1) Carbon nanotubes                                                                            ♦ CMOS compatible voltages                                                     techniques cannot be used                        2) Metal fibers and currents  ♦ Pigmented inks may be                                          infeasible, as                                   3) Conductive polymers such as                                                                 ♦ Easy extension from                                                          pigment particles may jam the bend               doped polythiophene                                                                            nozzles to pagewidth print                                                                   actuator                                         4) Carbon granules                                                                             heads                                                    Shape A shape memory alloy such as TiNi                                                              ♦ High force is available                                                      ♦ Fatigue limits                                                 maximum number of ♦                                                                IJ26                     memory                                                                               (also known as Nitinol - Nickel                                                                (stresses of hundreds of                                                                     cycles                                     alloy Titanium alloy developed at the                                                                MPa)          ♦ Low strain (1%) is                                             required to extend                               Naval Ordnance Laboratory) is                                                                  ♦ Large strain is available                                                    fatigue resistance                               thermally switched between its weak                                                            (more than 3%)                                                                               ♦ Cycle rate limited by                                          heat removal                                     martensitic state and its high                                                                 ♦ High corrosion resistance                                                    ♦ Requires unusual                                               materials (TiNi)                                 stiffness austenic state. The shape of                                                         ♦ Simple construction                                                          ♦ The latent heat of                                             transformation must                              the actuator in its martensitic state is                                                       ♦ Easy extension from                                                          be provided                                      deformed relative to the austenic                                                              nozzles to pagewidth print                                                                   ♦ High current                                                   operation                                        shape. The shape change causes                                                                 heads         ♦ Requires                                                       pre-stressing to distort the                     ejection of a drop.                                                                            ♦ Low voltage operation                                                        martensitic state                          Linear                                                                               Linear magnetic actuators include                                                              ♦ Linear Magnetic actuators                                                    ♦ Requires unusual                                               semiconductor     ♦                                                                IJ12                     Magnetic                                                                             the Linear Induction Actuator (LIA),                                                           can be constructed with                                                                      materials such as soft magnetic                                                alloys                                     Actuator                                                                             Linear Permanent Magnet                                                                        high thrust, long travel, and                                                                (e.g. CoNiFe [1])                                Synchronous Actuator (LPMSA),                                                                  high efficiency using planar                                                                 ♦ Some varieties also                                            require permanent                                Linear Reluctance Synchronous                                                                  semiconductor fabrication                                                                    magnetic materials such as                       Actuator (LRSA), Linear Switched                                                               techniques    Neodymium iron boron (NdFeB)                     Reluctance Actuator (LSRA), and                                                                ♦ Long actuator travel                                                         ♦ Requires complex                                               multi-phase drive                                the Linear Stepper Actuator (LSA).                                                             available     circuitry                                                        ♦ Medium force is available                                                    ♦ High current                                                   operation                                                        ♦ Low voltage operation                    __________________________________________________________________________     BASIC OPERATION MODE                                                           Operational                                                                    mode  Description     Advantages    Disadvantages     Examples                 __________________________________________________________________________     Actuator                                                                             This is the simplest mode of                                                                   ♦ Simple operation                                                             ♦ Drop repetition rate                                           is usually limited                                                                               ♦                                                                Thermal inkjet           directly                                                                             operation: the actuator directly                                                               ♦ No external fields                                                           to less than 10 KHz. However, this                                                               ♦                                                                Piezoelectric            pushes ink                                                                           supplies sufficient kinetic energy to                                                          ♦ Satellite drops can                                                          not fundamental to the method, but                                                               inkjet                         expel the drop. The drop must have a                                                           avoided if drop velocity is                                                                  related to the refill method                                                                     ♦                                                                IJ01, IJ02, IJ03,              sufficient velocity to overcome the                                                            less than 4 m/s                                                                              used              IJ04                           surface tension.                                                                               ♦ Can be efficient,                                                            ♦ All of the drop                                                kinetic energy must                                                                              ♦                                                                IJ05, IJ06, IJ07,                              upon the actuator used                                                                       provided by the actuator                                                                         IJ09                                                         ♦ Satellite drops                                                usually form if drop                                                                             ♦                                                                IJ11, IJ12, IJ14,                                            velocity is greater than 4.5                                                                     IJ16                                                                           ♦                                                                IJ20, IJ22, IJ23,                                                              IJ24                                                                           ♦                                                                IJ25, IJ26, IJ27,                                                              IJ28                                                                           ♦                                                                IJ29, IJ30, IJ31,                                                              IJ32                                                                           ♦                                                                IJ33, IJ34, IJ35,                                                              IJ36                                                                           ♦                                                                IJ37, IJ38, IJ39,                                                              IJ40                                                                           ♦                                                                IJ41, IJ42, IJ43,                                                              IJ44                     Proximity                                                                            The drops to be printed are selected                                                           ♦ Very simple print                                                            ♦ Requires close                                                 proximity between the                                                                            ♦                                                                Silverbrook, EP                by some manner (e.g. thermally                                                                 fabrication can be used                                                                      print head and the print media                                                                   0771 658 A2 and                induced surface tension reduction of                                                           ♦ The drop selection                                                           transfer roller   related patent                 pressurized ink). Selected drops are                                                           does not need to provide the                                                                 ♦ May require two print                                          heads printing    applications                   separated from the ink in the nozzle                                                           energy required to separate                                                                  alternate rows of the image                      by contact with the print medium or                                                            the drop from the nozzle                                                                     ♦ Monolithic color                                               print heads are                                  a transfer roller.            difficult                                  Electrostatic                                                                        The drops to be printed are selected                                                           ♦ Very simple print                                                            ♦ Requires very high                                             electrostatic field                                                                              ♦                                                                Silverbrook, EP          pull on ink                                                                          by some manner (e.g. thermally                                                                 fabrication can be used                                                                      ♦ Electrostatic field                                            for small nozzle  0771 658 A2 and                induced surface tension reduction of                                                           ♦ The drop selection                                                           sizes is above air breakdown                                                                     related patent                 pressurized ink). Selected drops are                                                           does not need to provide the                                                                 ♦ Electrostatic field                                            may attract dust  applications                   separated from the ink in the nozzle                                                           energy required to separate     ♦                                                                Tone-Jet                       by a strong electric field.                                                                    the drop from the nozzle                                 Magnetic                                                                             The drops to be printed are selected                                                           ♦ Very simple print                                                            ♦ Requires magnetic                                                                ♦                                                                Silverbrook, EP          pull on ink                                                                          by some manner (e.g. thermally                                                                 fabrication can be used                                                                      ♦ Ink colors other than                                          black are difficult                                                                              0771 658 A2 and                induced surface tension reduction of                                                           ♦ The drop selection                                                           ♦ Requires very high                                             magnetic fields   related patent                 pressurized ink). Selected drops are                                                           does not need to provide the    applications                   separated from the ink in the nozzle                                                           energy required to separate                                    by a strong magnetic field acting on                                                           the drop from the nozzle                                       the magnetic ink.                                                        Shutter                                                                              The actuator moves a shutter to                                                                ♦ High speed (>50 KHz)                                                         ♦ Moving parts are                                               required          ♦                                                                IJ13, IJ17, IJ21               block ink flow to the nozzle. The ink                                                          operation can be achieved                                                                    ♦ Requires ink pressure                                          modulator                                        pressure is pulsed at a multiple of the                                                        due to reduced refill time                                                                   ♦ Friction and wear                                              must be considered                               drop ejection frequency.                                                                       ♦ Drop timing can be                                                           ♦ Stiction is possible                             accurate                                                                       ♦ The actuator energy can be                                     very low                                                 Shuttered                                                                            The actuator moves a shutter to                                                                ♦ Actuators with small                                                         ♦ Moving parts are                                               required          ♦                                                                IJ08, IJ15, IJ18,        grill block ink flow through a grill to the                                                          can be used   ♦ Requires ink pressure                                          modulator         IJ19                           nozzle. The shutter movement need                                                              ♦ Actuators with small                                                         ♦ Friction and wear                                              must be considered                               only be equal to the width of the grill                                                        can be used   ♦ Stiction is possible             holes.          ♦ High speed (>50 KHz)                                           operation can be achieved                                Pulsed                                                                               A pulsed magnetic field attracts an                                                            ♦ Extremely low energy                                                         ♦ Requires an external                                           pulsed magnetic   ♦                                                                IJ10                     magnetic                                                                             `ink pusher` at the drop ejection                                                              operation is possible                                                                        field                                      pull on ink                                                                          frequency. An actuator controls a                                                              ♦ No heat dissipation                                                          ♦ Requires special                                               materials for both the                     pusher                                                                               catch, which prevents the ink pusher                                                           problems      actuator and the ink pusher                      from moving when a drop is not to                                                                            ♦ Complex construction             be ejected.                                                              __________________________________________________________________________     AUXILIARY MECHANISM (APPLIED TO ALL NOZZLES)                                   Auxiliary                                                                      Mechanism                                                                            Description     Advantages    Disadvantages     Examples                 __________________________________________________________________________     None  The actuator directly fires the ink                                                            ♦ Simplicity of construction                                                   ♦ Drop ejection energy                                           must be supplied  ♦                                                                Most inkjets,                  drop, and there is no external field or                                                        ♦ Simplicity of operation                                                      by individual nozzle                                                                             including                      other mechanism required.                                                                      ♦ Small physical size                                                                            piezoelectric and                                                              thermal bubble.                                                                ♦                                                                IJ01-IJ07, IJ09,                                                               IJ11                                                                           ♦                                                                IJ12, IJ14, IJ20,                                                              IJ22                                                                           ♦                                                                IJ23-IJ45                Oscillating                                                                          The ink pressure oscillates,                                                                   ♦ Oscillating ink pressure                                                     ♦ Requires external ink                                          pressure          ♦                                                                Silverbrook, EP          ink pressure                                                                         providing much of the drop ejection                                                            provide a refill pulse,                                                                      oscillator        0771 658 A2 and          (including                                                                           energy. The actuator selects which                                                             allowing higher operating                                                                    ♦ Ink pressure phase                                             and amplitude must                                                                               related patent           acoustic                                                                             drops are to be fired by selectively                                                           speed         be carefully controlled                                                                          applications             stimulation)                                                                         blocking or enabling nozzles. The                                                              ♦ The actuators may                                                            ♦ Acoustic reflections                                           in the ink chamber                                                                               ♦                                                                IJ08, IJ13, IJ15,              ink pressure oscillation may be                                                                with much lower energy                                                                       must be designed for                                                                             IJ17                           achieved by vibrating the print head,                                                          ♦ Acoustic lenses can be                                                                         ♦                                                                IJ18, IJ19, IJ21               or preferably by an actuator in the                                                            to focus the sound on the                                      ink supply.     nozzles                                                  Media The print head is placed in close                                                              ♦ Low power                                                                    ♦ Precision assembly                                             required          ♦                                                                Silverbrook, EP          proximity                                                                            proximity to the print medium.                                                                 ♦ High accuracy                                                                ♦ Paper fiber's may                                              cause problems    0771 658 A2 and                Selected drops protrude. from the                                                              ♦ Simple print head                                                            ♦ Cannot print on rough                                          substrates        related patent                 print head further than unselected                                                             construction                    applications                   drops, and contact the print medium.                                           The drop soaks into the medium fast                                            enough to cause drop separation.                                         Transfer                                                                             Drops are printed to a transfer roller                                                         ♦ High accuracy                                                                ♦ Bulky                                                                            ♦                                                                Silverbrook, EP          roller                                                                               instead of straight to the print                                                               ♦ Wide range of print                                                          ♦ Expensive                                                                        0771 658 A2 and                medium. A transfer roller can also be                                                          substrates can be used                                                                       ♦ Complex                                                                          related patent                 used for proximity drop separation.                                                            ♦ Ink can be dried on                                                                            applications                                   transfer roller                 ♦                                                                Tektronix hot                                                                  melt piezoelectric                                                             inkjet                                                                         ♦ Any                                                            of the IJ                                                                      series                   Electrostatic                                                                        An electric field is used to accelerate                                                        ♦ Low power                                                                    ♦ Field strength                                                 required for separation                                                                          ♦                                                                Silverbrook, EP                selected drops towards the print                                                               ♦ Simple print head                                                            of small drops is near or above                                                                  0771 658 A2 and                medium.         construction  breakdown         related patent                                                                 applications                                                                   ♦                                                                Tone-jet                 Direct                                                                               A magnetic field is used to accelerate                                                         ♦ Low power                                                                    ♦ Requires magnetic                                                                ♦                                                                Silverbrook, EP          magnetic                                                                             selected drops of magnetic ink                                                                 ♦ Simple print head                                                            ♦ Requires strong                                                magnetic field    0771 658 A2 and          field towards the print medium.                                                                      construction                    related patent                                                                 applications             Cross The print head is placed in a constant                                                         ♦ Does not require magnetic                                                    ♦ Requires external                                              magnet            ♦                                                                IJ06, IJ16               magnetic                                                                             magnetic field. The Lorenz force in a                                                          materials to be integrated in                                                                ♦ Current densities may                                          be high,                                   field current carrying wire is used to move                                                          the print head                                                                               resulting in electromigration                                                  problems                                         the actuator.   manufacturing process                                    Pulsed                                                                               A pulsed magnetic field is used to                                                             ♦ Very low power operation                                                     ♦ Complex print head                                             construction      ♦                                                                IJ10                     magnetic                                                                             cyclically attract a paddle, which                                                             is possible   ♦ Magnetic materials                                             required in print                          field pushes on the ink. A small actuator                                                            ♦ Small print head size                                                        head                                             moves a catch, which selectively                                               prevents the paddle from moving.                                         __________________________________________________________________________     ACTUATOR AMPLIFICATION OR MODIFICATION METHOD                                  Actuator                                                                       amplification                                                                        Description     Advantages    Disadvantages     Examples                 __________________________________________________________________________     None  No actuator mechanical                                                                         ♦ Operational simplicity                                                       ♦ Many actuator                                                  mechanisms have   ♦                                                                Thermal Bubble                 amplification is used. The actuator                                                                          insufficient travel, or insufficient                                           force,            Inkjet                         directly drives the drop ejection                                                                            to efficiently drive the drop                                                  ejection          ♦                                                                IJ01, IJ02, IJ06,              process.                      process           IJ07                                                                           ♦                                                                IJ16, IJ25, IJ26         Differential                                                                         An actuator material expands more                                                              ♦ Provides greater travel in                                                   ♦ High stresses are                                              involved          ♦                                                                Piezoelectric            expansion                                                                            on one side than on the other. The                                                             reduced print head area                                                                      ♦ Care must be taken                                             that the materials                                                                               ♦                                                                IJ03, IJ09, IJ17-        bend  expansion may be thermal,                                                                      ♦ The bend actuator                                                            do not delaminate IJ24                     actuator                                                                             piezoelectric, magnetostrictive, or                                                            a high force low travel                                                                      ♦ Residual bend                                                  resulting from high                                                                              ♦                                                                IJ27, IJ29-IJ39,               other mechanism.                                                                               actuator mechanism to high                                                                   temperature or high stress                                                                       IJ42,g                                         travel, lower force                                                                          formation         ♦                                                                IJ43, IJ44                                     mechanism.                                               Transient                                                                            A trilayer bend actuator where the                                                             ♦ Very good temperature                                                        ♦ High stresses are                                              involved          ♦                                                                IJ40, IJ41               bend  two outside layers are identical. This                                                         stability     ♦ Care must be taken                                             that the materials                         actuator                                                                             cancels bend due to ambient                                                                    ♦ High speed, as a new                                                         do not delaminate                                temperature and residual stress. The                                                           can be fired before heat                                       actuator only responds to transient                                                            dissipates                                                     heating of one side or the other.                                                              ♦ Cancels residual stress of                                     formation                                                Actuator                                                                             A series of thin actuators are stacked.                                                        ♦ Increased travel                                                             ♦ Increased fabrication                                          complexity        ♦                                                                Some                     stack This can be appropriate where                                                                  ♦ Reduced drive voltage                                                        ♦ Increased possibility                                          of short circuits piezoelectric ink              actuators require high electric field                                                                        due to pinholes   jets                           strength, such as electrostatic and             ♦                                                                IJ04                           piezoelectric actuators.                                                 Multiple                                                                             Multiple smaller actuators are used                                                            ♦ Increases the force                                                          ♦ Actuator forces may                                            not add linearly, ♦                                                                IJ12, IJ13, IJ18,        actuators                                                                            simultaneously to move the ink.                                                                from an actuator                                                                             reducing efficiency                                                                              IJ20                           Each actuator need provide only a                                                              ♦ Multiple actuators can                                                                         ♦                                                                IJ22, IJ28, IJ42,              portion of the force required.                                                                 positioned to control ink       IJ43                                           flow accurately                                          Linear                                                                               A linear spring is used to transform a                                                         ♦ Matches low travel                                                           ♦ Requires print head                                            area for the spring                                                                              ♦                                                                IJ15                     Spring                                                                               motion with small travel and high                                                              with higher travel                                             force into a longer travel, lower force                                                        requirements                                                   motion.         ♦ Non-contact method of                                          motion transformation                                    Reverse                                                                              The actuator loads a spring. When                                                              ♦ Better coupling to the                                                       ♦ Fabrication                                                    complexity        ♦                                                                IJ05, IJ11               spring                                                                               the actuator is turned off, the spring                                                                       ♦ High stress in the                                             spring                                           releases. This can reverse the                                                 force/distance curve of the actuator                                           to make it compatible with the                                                 force/time requirements of the drop                                            ejection.                                                                Coiled                                                                               A bend actuator is coiled to provide                                                           ♦ Increases travel                                                             ♦ Generally restricted                                           to planar         ♦                                                                IJ17, IJ21, IJ34,        actuator                                                                             greater travel in a reduced chip area.                                                         ♦ Reduces chip area                                                            implementations due to                                                                           IJ35eme                                        ♦ Planar implementations                                                       fabrication difficulty in other                                  relatively easy to fabricate.                                                                orientations.                              Flexure bend                                                                         A bend actuator has a small region                                                             ♦ Simple means of increasing                                                   ♦ Care must be taken                                             not to exceed the ♦                                                                IJ10, IJ19, IJ33         actuator                                                                             near the fixture point, which flexes                                                           travel of a bend actuator                                                                    elastic limit in the flexure area                much more readily than the    ♦ Stress distribution                                            is very uneven                                   remainder of the actuator. The                                                                               ♦ Difficult to                                                   accurately model with                            actuator flexing is effectively                                                                              finite element analysis                          converted from an even coiling to an                                           angular bend, resulting in greater                                             travel of the actuator tip.                                              Gears Gears can be used to increase travel                                                           ♦ Low force, low travel                                                        ♦ Moving parts are                                               required          ♦                                                                IJ13                           at the expense of duration. Circular                                                           actuators can be used                                                                        ♦ Several actuator                                               cycles are required                              gears, rack and pinion, ratchets, and                                                          ♦ Can be fabricated                                                            ♦ More complex drive                                             electronics                                      other gearing methods can be used.                                                             standard surface MEMS                                                                        ♦ Complex construction                             processes     ♦ Friction, friction,                                            and wear are possible                      Catch The actuator controls a small catch.                                                           ♦ Very low actuator                                                            ♦ Complex                                                                          ♦                                                                IJ10                           The catch either enables or disables                                                           ♦ Very small actuator                                                          ♦ Requires external                                              force                                            movement of an ink pusher that is                                                                            ♦ Unsuitable for                                                 pigmented inks                                   controlled in a bulk manner.                                             Buckle plate                                                                         A buckle plate can be used to change                                                           ♦ Very fast movement                                                           ♦ Must stay within                                               elastic limits of the                                                                            ♦ S.                                                             Hirata et al,                  a slow actuator into a fast motion. It                                                         achievable    materials for long device                                                                        "An Ink-jet                    can also convert a high force, low                                                                           ♦ High stresses                                                  involved          Head . . . ",                  travel actuator into a high travel,                                                                          ♦ Generally high power                                           requirement       Proc. IEEE MEMS,               medium force motion.                            Feb. 1996, pp 418-                                                             423.                                                                           ♦                                                                IJ18, IJ27               Tapered                                                                              A tapered magnetic pole can increase                                                           ♦ Linearizes the magnetic                                                      ♦ Complex                                                                          ♦                                                                IJ14                     magnetic                                                                             travel at the expense of force.                                                                force/distance curve                                     pole                                                                           Lever A lever and fulcrum is used to                                                                 ♦ Matches low travel                                                           ♦ High stress around                                             the fulcrum       ♦                                                                IJ32, IJ36, IJ37               transform a motion with small travel                                                           with higher travel                                             and high force into a motion with                                                              requirements                                                   longer travel and lower force. The                                                             ♦ Fulcrum area has no linear                     lever can also reverse the direction of                                                        movement, and can be used                                      travel.         for a fluid seal                                         Rotary                                                                               The actuator is connected to a rotary                                                          ♦ High mechanical advantage                                                    ♦ Complex                                                                          ♦                                                                IJ28                     impeller                                                                             impeller. A small angular deflection                                                           ♦ The ratio of force to                                                        ♦ Unsuitable for                                                 pigmented inks                                   of the actuator results in a rotation of                                                       of the actuator can be                                         the impeller vanes, which push the                                                             matched to the nozzle                                          ink against stationary vanes and out                                                           requirements by varying the                                    of the nozzle.  number of impeller vanes                                 Acoustic                                                                             A refractive or diffractive (e.g. zone                                                         ♦ No moving parts                                                              ♦ Large area                                                                       ♦                                                                1993 Hadimioglu          lens  plate) acoustic lens is used to                                                                              ♦ Only relevant for                                              acoustic ink jets et al, EUP 550,192             concentrate sound waves.                        ♦                                                                1993 Elrod et al,                                                              EUP 572,220              Sharp A sharp point is used to concentrate                                                           ♦ Simple construction                                                          ♦ Difficult to                                                   fabricate using standard                                                                         ♦                                                                Tone-jet                 conductive                                                                           an electrostatic field.       VLSI processes for a surface ejecting      point                               ink-jet                                                                        ♦ Only relevant for                                              electrostatic ink jets                     __________________________________________________________________________     ACTUATOR MOTION                                                                Actuator                                                                       motion                                                                               Description     Advantages    Disadvantages     Examples                 __________________________________________________________________________     Volume                                                                               The volume of the actuator changes,                                                            ♦ Simple construction in                                                       ♦ High energy is                                                 typically required to                                                                            ♦                                                                Hewlett-Packard          expansion                                                                            pushing the ink in all directions.                                                             case of thermal inkjet                                                                       achieve volume expansion. This                                                                   Thermal Inkjet                                               to thermal stress, cavitation,                                                                   ♦                                                                Canon Bubblejet                                              kogation in thermal ink jet                                                    implementations                            Linear,                                                                              The actuator moves in a direction                                                              ♦ Efficient coupling to                                                        ♦ High fabrication                                               complexity may be ♦                                                                IJ01, IJ02, IJ04,        normal to                                                                            normal to the print head surface. The                                                          drops ejected normal to the                                                                  required to achieve                                                                              IJ07endicular            chip surface                                                                         nozzle is typically in the line of                                                             surface       motion            ♦                                                                IJ11, IJ14                     movement.                                                                Linear,                                                                              The actuator moves parallel to the                                                             ♦ Suitable for planar                                                          ♦ Fabrication                                                    complexity        ♦                                                                IJ12, IJ13, IJ15,        parallel to                                                                          print head surface. Drop ejection                                                              fabrication   ♦ Friction                                                                         IJ33,                    chip surface                                                                         may still be normal to the surface.                                                                          ♦ Stiction                                                                         ♦                                                                IJ34, IJ35, IJ36         Membrane                                                                             An actuator with a high force but                                                              ♦ The effective area of                                                        ♦ Fabrication                                                    complexity        ♦                                                                1982 Howkins             push  small area is used to push a stiff                                                             actuator becomes the                                                                         ♦ Actuator                                                                         U.S. Pat. No.                  membrane that is in contact with the                                                           membrane area ♦ Difficulty of                                                  integration in a VLSI                                                                            4,459,601                      ink.                          process                                    Rotary                                                                               The actuator causes the rotation of                                                            ♦ Rotary levers may be                                                         ♦ Device                                                                           ♦                                                                IJ05, IJ08, IJ13,              some element, such a grill or                                                                  to increase travel                                                                           ♦ May have friction at                                           a pivot point     IJ28                           impeller        ♦ Small chip area                                                requirements                                             Bend  The actuator bends when energized.                                                             ♦ A very small change                                                          ♦ Requires the actuator                                          to be made from   ♦                                                                1970 Kyser et al               This may be due to differential                                                                dimensions can be                                                                            at least two distinct layers, or to                                            have a            U.S. Pat. No.                  thermal expansion, piezoelectric                                                               converted to a large motion.                                                                 thermal difference across the                                                  actuator          3,946,398                      expansion, magnetostriction, or other           ♦                                                                1973 Stemme                    form of relative dimensional change.            U.S. Pat. No.                                                                  3,747,120                                                                      ♦                                                                IJ03, IJ09, IJ10,                                                              IJ19                                                                           ♦                                                                IJ23, IJ24, IJ25,                                                              IJ29                                                                           ♦                                                                IJ30, IJ31, IJ33,                                                              IJ34                                                                           ♦                                                                IJ35                     Swivel                                                                               The actuator swivels around a central                                                          ♦ Allows operation where                                                       ♦ Inefficient coupling                                           to the ink motion ♦                                                                IJ06                           pivot. This motion is suitable where                                                           net linear force on the                                        there are opposite forces applied to                                                           paddle is zero                                                 opposite sides of the paddle, e.g.                                                             ♦ Small chip area                                Lorenz force.   requirements                                             Straighten                                                                           The actuator is normally bent, and                                                             ♦ Can be used with shape                                                       ♦ Requires careful                                               balance of stresses                                                                              ♦                                                                IJ26, IJ32                     straightens when energized.                                                                    memory alloys where the                                                                      ensure that the quiescent bend is                                austenic phase is planar                                                                     accurate                                   Double bend                                                                          The actuator bends in one direction                                                            ♦ One actuator can be used                                                     ♦ Difficult to make the                                          drops ejected by  ♦                                                                IJ36, IJ37, IJ38               when one element is energized, and                                                             power two nozzles.                                                                           both bend directions identical.                  bends the other way when another                                                               ♦ Reduced chip size.                                                           ♦ A small efficiency                                             loss compared to                                 element is energized.                                                                          ♦ Not sensitive to ambient                                                     equivalent single bend actuators.                                temperature                                              Shear Energizing the actuator causes a                                                               ♦ Can increase the effective                                                   ♦ Not readily                                                    applicable to other                                                                              ♦                                                                1985 Fishbeck                  shear motion in the actuator material.                                                         travel of piezoelectric                                                                      mechanisms        U.S. Pat. No.                                  actuators                       4,584,590                Radial                                                                               The actuator squeezes an ink                                                                   ♦ Relatively easy to                                                           ♦ High force                                                                       ♦                                                                1970 Zoltan U.S.         constriction                                                                         reservoir, forcing ink from a                                                                  single nozzles from glass                                                                    ♦ Inefficient                                                                      Pat. No. 3,683,212             constricted nozzle.                                                                            tubing as macroscopic                                                                        ♦ Difficult to                                                   integrate with VLSI                                              structures    processes                                  Coil/uncoil                                                                          A coiled actuator uncoils or coils                                                             ♦ Easy to fabricate as a                                                       ♦ Difficult to                                                   fabricate for non-planar                                                                         ♦                                                                IJ17, IJ21, IJ34,              more tightly. The motion of the free                                                           VLSI process  devices           IJ35                           end of the actuator ejects the ink.                                                            ♦ Small area required,                                                         ♦ Poor out-of-plane                                              stiffness                                                        therefore low cost                                       Bow   The actuator bows (or buckles) in the                                                          ♦ Can increase the speed                                                       ♦ Maximum travel is                                              constrained       ♦                                                                IJ16, IJ18, IJ27               middle when energized.                                                                         travel        ♦ High force required                              ♦ Mechanically rigid                       Push-Pull                                                                            Two actuators control a shutter. One                                                           ♦ The structure is pinned                                                      ♦ Not readily suitable                                           for inkjets which ♦                                                                IJ18                           actuator pulls the shutter, and the                                                            both ends, so has a high                                                                     directly push the ink                            other pushes it.                                                                               out-of-plane rigidity                                    Curl inwards                                                                         A set of actuators curl inwards to                                                             ♦ Good fluid flow to                                                           ♦ Design                                                                           ♦                                                                IJ20, IJ42                     reduce the volume of ink that they                                                             region behind the actuator                                     enclose.        increases efficiency                                     Curl  A set of actuators curl outwards,                                                              ♦ Relatively simple                                                            ♦ Relatively large chip                                          area              ♦                                                                IJ43                     outwards                                                                             pressurizing ink in a chamber                                                                  construction                                                   surrounding the actuators, and                                                 expelling ink from a nozzle in the                                             chamber.                                                                 Iris  Multiple vanes enclose a volume of                                                             ♦ High efficiency                                                              ♦ High fabrication                                               complexity        ♦                                                                IJ22                           ink. These simultaneously rotate,                                                              ♦ Small chip area                                                              ♦ Not suitable for                                               pigmented inks                                   reducing the volume between the                                                vanes.                                                                   Acoustic                                                                             The actuator vibrates at a high                                                                ♦ The actuator can be                                                          ♦ Large area required                                            for efficient     ♦                                                                1993 Hadimioglu          vibration                                                                            frequency.      physically distant from the                                                                  operation at useful                                                                              et al, EUP 550,192                             ink           ♦ Acoustic coupling and                                          crosstalk         ♦                                                                1993 Elrod et al,                                            ♦ Complex drive                                                  circuitry         EUP 572,220                                                  ♦ Poor control of drop                                           volume and                                                                     position                                   None  In various ink jet designs the actuator                                                        ♦ No moving parts                                                              ♦ Various other                                                  tradeoffs are required                                                                           ♦                                                                Silverbrook, EP                does not move.                eliminate moving parts                                                                           0771 658 A2 and                                                                related patent                                                                 applications                                                                   ♦                                                                Tone-jet                 __________________________________________________________________________     NOZZLE REFILL METHOD                                                           Nozzle refill                                                                  method                                                                               Description     Advantages    Disadvantages     Examples                 __________________________________________________________________________     Surface                                                                              After the actuator is energized, it                                                            ♦ Fabrication simplicity                                                       ♦ Low                                                                              ♦                                                                Thermal inkjet           tension                                                                              typically returns rapidly to its normal                                                        ♦ Operational simplicity                                                       ♦ Surface tension force                                          relatively small  ♦                                                                Piezoelectric                  position. This rapid return sucks in                                                                         compared to actuator                                                                             inkjet                         air through the nozzle opening. The                                                                          ♦ Long refill time                                               usually dominates the                                                                            ♦                                                                IJ01-IJ07,                     ink surface tension at the nozzle then                                                                       total repetition rate                                                                            IJ10-IJ14                      exerts a small force restoring the              ♦                                                                IJ16, IJ20, IJ22-              meniscus to a minimum area.                     IJ45                     Shuttered                                                                            Ink to the nozzle chamber is                                                                   ♦ High speed                                                                   ♦ Requires common ink                                            pressure          ♦                                                                IJ08, IJ13, IJ15,        oscillating                                                                          provided at a pressure that oscillates                                                         ♦ Low actuator energy, as                                                      oscillator        IJ17                     ink pressure                                                                         at twice the drop ejection frequency.                                                          actuator need only open or                                                                   ♦ May not be suitable                                            for pigmented inks                                                                               ♦                                                                IJ18, IJ19, IJ21               When a drop is to be ejected, the                                                              close the shutter, instead of                                  shutter is opened for 3 half cycles:                                                           ejecting the ink drop                                          drop ejection, actuator return, and                                            refill.                                                                  Refill                                                                               After the main actuator has ejected a                                                          ♦ High speed, as the nozzle                                                    ♦ Requires two                                                   independent actuators                                                                            ♦                                                                IJ09                     actuator                                                                             drop a second (refill) actuator is                                                             actively refilled                                                                            nozzle                                           energized. The refill actuator pushes                                          ink into the nozzle chamber. The                                               refill actuator returns slowly, to                                             prevent its return from, emptying the                                          chamber again.                                                           Positive ink                                                                         The ink is held a slight positive                                                              ♦ High refill rate, therefore                                                  ♦ Surface spill must be                                          prevented         ♦                                                                Silverbrook, EP          pressure                                                                             pressure. After the ink drop is                                                                high drop repetition rate is                                                                 ♦ Highly hydrophobic                                             print head        0771 658 A2 and                ejected, the nozzle chamber fills                                                              possible      surfaces are required                                                                            related patent                 quickly as surface tension and ink              applications                   pressure both operate to refill the             ♦                                                                Alternative for:               nozzle.                                         ♦                                                                IJ01-IJ07,                                                                     IJ10-IJ14                                                                      ♦                                                                IJ16, IJ20, IJ22-                                                              IJ45                     __________________________________________________________________________     METHOD OF RESTRICTING BACK-FLOW THROUGH INLET                                  Inlet                                                                          back-flow                                                                      restriction                                                                    method                                                                               Description     Advantages    Disadvantages     Examples                 __________________________________________________________________________     Long inlet                                                                           The ink inlet channel to the nozzle                                                            ♦ Design simplicity                                                            ♦ Restricts refill                                                                 ♦                                                                Thermal inkjet           channel                                                                              chamber is made long and, relatively                                                           ♦ Operational simplicity                                                       ♦ May result in a                                                relatively large chip                                                                            ♦                                                                Piezoelectric                  narrow, relying on viscous drag to                                                             ♦ Reduces crosstalk                                                            area              inkjet                         reduce inlet back-flow.       ♦ Only partially                                                 effective         ♦                                                                IJ42, IJ43               Positive ink                                                                         The ink is under a positive pressure,                                                          ♦ Drop selection and                                                           ♦ Requires a method                                              (such as a nozzle ♦                                                                Silverbrook, EP          pressure                                                                             so that in the quiescent state some of                                                         separation forces can be                                                                     rim or effective hydrophobizing,                                                                 0771 658 A2 and                the ink drop already protrudes from                                                            reduced       both) to prevent flooding of                                                                     related patent                 the nozzle.     ♦ Fast refill time                                                             ejection surface of the print                                                                    applications                   This reduces the pressure in the                ♦                                                                Possible                       nozzle chamber which is required to             operation of the               eject a certain volume of ink. The              following:                     reduction in chamber pressure results           ♦                                                                IJ01-IJ07, IJ09-               in a reduction in ink pushed out                IJ12                           through the inlet.                              ♦                                                                IJ14, IJ16, IJ20,                                                              IJ22,                                                                          ♦                                                                IJ23-IJ34, IJ36-                                                               IJ41                                                                           ♦                                                                IJ44                     Baffle                                                                               One or more baffles are placed in the                                                          ♦ The refill rate is not                                                       ♦ Design                                                                           ♦ HP                                                             Thermal Ink                    inlet ink flow. When the actuator is                                                           restricted as the long inlet                                                                 ♦ May increase                                                   fabrication complexity                                                                           Jet                            energized, the rapid ink movement                                                              method.       (e.g. Tektronix hot melt                                                       Piezoelectric     ♦                                                                Tektronix                      creates eddies which restrict the flow                                                         ♦ Reduces crosstalk                                                            print heads).     piezoelectric ink                                                              jet                            through the inlet. The slower refill                                           process is unrestricted, and does not                                          result in eddies.                                                        Flexible flap                                                                        In this method recently disclosed by                                                           ♦ Significantly reduces                                                        ♦ Not applicable to                                              most inkjet       ♦                                                                Canon                    restricts inlet                                                                      Canon, the expanding actuator                                                                  flow for edge-shooter                                                                        configurations                                   (bubble) pushes on a flexible flap                                                             thermal ink jet devices                                                                      ♦ Increased fabrication                                          complexity                                       that restricts the inlet.     ♦ Inelastic deformation                                          of polymer flap                                                                results in creep over extended use         Inlet filter                                                                         A filter is located between the ink                                                            ♦ Additional advantage of                                                      ♦ Restricts refill                                                                 ♦                                                                IJ04, IJ12, IJ24,              inlet and the nozzle chamber. The                                                              filtration    ♦ May result in complex                                          construction      IJ27                           filter has a multitude of small holes                                                          ♦ Ink filter may be                                                                              ♦                                                                IJ29, IJ30                     or slots, restricting ink flow. The                                                            with no additional process                                     filter also removes particles which                                                            steps                                                          may block the nozzle.                                                    Small inlet                                                                          The ink inlet channel to the nozzle                                                            ♦ Design simplicity                                                            ♦ Restricts refill                                                                 ♦                                                                IJ02, IJ37, IJ44         compared to                                                                          chamber has a substantially smaller                                                                          ♦ May result in a                                                relatively large chip                      nozzle                                                                               cross section than that of the nozzle,                                                                       area                                             resulting in easier ink egress out of                                                                        ♦ Only partially                                                 effective                                        the nozzle than out of the inlet.                                        Inlet shutter                                                                        A secondary actuator controls the                                                              ♦ Increases speed of the                                                       ♦ Requires separate                                              refill actuator and                                                                              ♦                                                                IJ09                           position of a shutter, closing off the                                                         jet print head operation                                                                     drive circuit                                    ink inlet when the main actuator is                                            energized.                                                               The inlet is                                                                         The method avoids the problem of                                                               ♦ Back-flow problem                                                            ♦ Requires careful                                               design to minimize                                                                               ♦                                                                IJ01, IJ03, IJ05,        located be-                                                                          inlet back-flow by arranging the ink-                                                          eliminated    the negative pressure behind the                                               paddle            IJ06                     hind the ink-                                                                        pushing surface of the actuator                 ♦                                                                IJ07, IJ10, IJ11,        pushing                                                                              between the inlet and the nozzle.               IJ14                     surface                                               ♦                                                                IJ16, IJ22, IJ23,                                                              IJ25                                                                           ♦                                                                IJ28, IJ31, IJ32,                                                              IJ33                                                                           ♦                                                                IJ34, IJ35, IJ36,                                                              IJ39                                                                           ♦                                                                IJ40, IJ41               Part of the                                                                          The actuator and a wall of the ink                                                             ♦ Significant reductions                                                       ♦ small increase in                                              fabrication       ♦                                                                IJ07, IJ20, IJ26,        actuator                                                                             chamber are arranged so that the                                                               back-flow can be achieved                                                                    complexity        IJ38                     moves to                                                                             motion of the actuator closes off the                                                          ♦ Compact designs possible                 shut off the                                                                         inlet.                                                                   inlet                                                                          Nozzle                                                                               In some configurations of ink jet,                                                             ♦ Ink back-flow problem                                                        ♦ None related to ink                                            back-flow on      ♦                                                                Silverbrook, EP          actuator does                                                                        there is no expansion or movement                                                              eliminated    actuation         0771 658 A2 and          not result in                                                                        of an actuator which may cause ink              related patent           ink   back-flow through the inlet.                    applications             back-flow                                             ♦                                                                Valve-jet                                                                      ♦                                                                Tone-jet                                                                       ♦                                                                IJ08, IJ13, IJ15,                                                              IJ17                                                                           ♦                                                                IJ18, IJ19,              __________________________________________________________________________                                                           IJ21                     NOZZLE CLEARING METHOD                                                         Nozzle                                                                         Clearing                                                                       method                                                                               Description     Advantages    Disadvantages     Examples                 __________________________________________________________________________     Normal                                                                               All of the nozzles are fired                                                                   ♦ No added complexity on                                                       ♦ May not be sufficient                                          to displace dried ♦                                                                Most ink jet             nozzle firing                                                                        periodically, before the ink has a                                                             print head    ink               systems                        chance to dry. When not in use the              ♦                                                                IJ01-IJ07, IJ09-               nozzles are sealed (capped) against             IJ12                           air.                                            ♦                                                                IJ14, IJ16, IJ20,              The nozzle firing is usually                    IJ22                           performed during a special clearing             ♦                                                                IJ23-IJ34, IJ36-               cycle, after first moving the print             IJ45                           head to a cleaning station.                                              Extra power                                                                          In systems which heat the ink, but do                                                          ♦ Can be highly effective                                                      ♦ Requires higher drive                                          voltage for       ♦                                                                Silverbrook, EP          to ink heater                                                                        not boil it under normal, situations,                                                          the heater is adjacent to the                                                                clearing          0771 658 A2 and                nozzle clearing can be achieved by                                                             nozzle        ♦ May require larger                                             drive transistors related patent                 over-powering the heater and boiling            applications                   ink at the nozzle.                                                       Rapid The actuator is fired in rapid                                                                 ♦ Does not require extra                                                       ♦ Effectiveness depends                                          substantially     ♦ May                                                            be used                  succession of                                                                        succession. In some configurations,                                                            circuits on the print head                                                                   upon the configuration of the                                                                    with:t                   actuator                                                                             this may cause heat build-up at the                                                            ♦ Can be readily controlled                                                    nozzle            ♦                                                                IJ01-IJ07, IJ09-         pulses                                                                               nozzle which boils the ink, clearing                                                           and initiated by digital logic  IJ11                           the nozzle. In other situations, it may         ♦                                                                IJ14, IJ16, IJ20,              cause sufficient vibrations to                  IJ22                           dislodge clogged nozzles.                       ♦                                                                IJ23-IJ25, IJ27-                                                               IJ34                                                                           ♦                                                                IJ36-IJ45                Extra power                                                                          Where an actuator is not normally                                                              ♦ A simple solution                                                            ♦ Not suitable where                                             there is a hard limit                                                                            ♦ May                                                            be used                  to ink                                                                               driven to the limit of its motion,                                                             applicable    to actuator movement                                                                             with:                    pushing                                                                              nozzle clearing may be assisted by              ♦                                                                IJ03, IJ09, IJ16,        actuator                                                                             providing an enhanced drive signal              IJ20                           to the actuator.                                ♦                                                                IJ23, IJ24, IJ25,                                                              IJ27                                                                           ♦                                                                IJ29, IJ30, IJ31,                                                              IJ32                                                                           ♦                                                                IJ39, IJ40, IJ41,                                                              IJ42                                                                           ♦                                                                IJ43, IJ44, IJ45         Acoustic                                                                             An ultrasonic wave is applied to the                                                           ♦ A high nozzle clearing                                                       ♦ High implementation                                            cost if system    ♦                                                                IJ08, IJ13, IJ15,        resonance                                                                            ink chamber. This wave is of an                                                                capability can be achieved                                                                   does not already include an                                                                      IJ17stic                       appropriate amplitude and frequency                                                            ♦ May be implemented                                                           actuator          ♦                                                                IJ18, IJ19, IJ21               to cause sufficient force at the nozzle                                                        very low cost in systems                                       to clear blockages. This is easiest to                                                         which already include                                          achieve if the ultrasonic wave is at a                                                         acoustic actuators                                             resonant frequency of the ink cavity.                                    Nozzle                                                                               A microfabricated plate is pushed                                                              ♦ Can clear severely                                                           ♦ Accurate mechanical                                            alignment is      ♦                                                                Silverbrook, EP          clearing                                                                             against the nozzles. The plate has a                                                           nozzles       required          0771 658 A2 and          plate post for every nozzle. The array of                                                                          ♦ Moving parts are                                               required          related patent                 posts                         ♦ There is risk of                                               damage to the nozzles                                                                            applications                                                 ♦ Accurate fabrication                                           is required                                Ink pressure                                                                         The pressure of the ink is                                                                     ♦ May be effective where                                                       ♦ Requires pressure                                              pump or other     ♦ May                                                            be used with             pulse temporarily increased so that ink                                                              other methods cannot be                                                                      pressure actuator all IJ series ink                                                              jets                           streams from all of the nozzles. This                                                          used          ♦ Expensive                        may be used in conjunction with                                                                              ♦ Wasteful of ink                  actuator energizing.                                                     Print head                                                                           A flexible `blade` is wiped across the                                                         ♦ Effective for planar                                                         ♦ Difficult to use if                                            print head surface is                                                                            ♦                                                                Many ink jet             wiper print head surface. The blade is                                                               head surfaces non-planar or very fragile                                                                       systems                        usually fabricated from a flexible                                                             ♦ Low cost                                                                     ♦ Requires mechanical                                            parts                                            polymer, e.g. rubber or synthetic                                                                            ♦ Blade can wear out in                                          high volume                                      elastomer.                    print systems                              Separate ink                                                                         A separate heater is provided at the                                                           ♦ Can be effective where                                                       ♦ Fabrication                                                    complexity        ♦ Can                                                            be used with             boiling                                                                              nozzle although the normal drop e-                                                             other nozzle clearing           many IJ series ink       heater                                                                               ection mechanism does not require it.                                                          methods cannot be used          jets                           The heaters do not require individual                                                          ♦ Can be implemented at no                       drive circuits, as many nozzles can                                                            additional cost in some                                        be cleared simultaneously, and no                                                              inkjet configurations                                          imaging is required.                                                     __________________________________________________________________________     NOZZLE PLATE CONSTRUCTION                                                      Nozzle plate                                                                   construction                                                                         Description     Advantages    Disadvantages     Examples                 __________________________________________________________________________     Electro-                                                                             A nozzle plate is separately                                                                   ♦ Fabrication simplicity                                                       ♦ High temperatures and                                          pressures are     ♦                                                                Hewlett Packard          formed                                                                               fabricated from electroformed nickel,                                                                        required to bond nozzle                                                                          Thermal Inkjet           nickel                                                                               and bonded to the print head chip.                                                                           ♦ Minimum thickness                                              constraints                                                                    ♦ Differential thermal                                           expansion                                  Laser ablated                                                                        Individual nozzle holes are ablated                                                            ♦ No masks required                                                            ♦ Each hole must be                                              individually formed                                                                              ♦                                                                Canon Bubblejet          or drilled                                                                           by an intense UV laser in a nozzle                                                             ♦ Can be quite fast                                                            ♦ Special equipment                                              required          ♦                                                                1988 Sercel et           polymer                                                                              plate, which is typically a polymer                                                            ♦ Some control over                                                            ♦ Slow where there are                                           many thousands    al., SPIE, Vol.                                                                998                            such as polyimide or polysulphone                                                              profile is possible                                                                          of nozzles per print                                                                             Excimer Beam                                   ♦ Equipment required                                                           ♦ May produce thin                                               burrs at exit holes                                                                              Applications, pp.                              relatively low cost             76-83                                                                          ♦                                                                1993 Watanabe et                                                               al., U.S. Pat. No.                                                             5,208,604                Silicon                                                                              A separate nozzle plate is                                                                     ♦ High accuracy is attainable                                                  ♦ Two part                                                                         ♦ K.                                                             Bean, IEEE               micro-                                                                               micromachined from single crystal                                                                            ♦ High                                                                             Transactions on          machined                                                                             silicon, and bonded to the print head                                                                        ♦ Requires precision                                             alignment         Electron Devices,              wafer.                        ♦ Nozzles may be                                                 clogged by adhesive                                                                              Vol. ED-25, No 10,                                                             1978, pp 1185-1195                                                             ♦                                                                Xerox 1990                                                                     Hawkins et al.,                                                                U.S. Pat. No.                                                                  4,899,181                Glass Fine glass capillaries are drawn from                                                          ♦ No expensive equipment                                                       ♦ Very small nozzle                                              sizes are difficult                                                                              ♦                                                                1970 Zoltan U.S.         capillaries                                                                          glass tubing. This method has been                                                             required      form              Pat. No. 3,683,212             used for making individual nozzles,                                                            ♦ Simple to make single                                                        ♦ Not suited for mass                                            production                                       but is difficult to use for bulk                                                               nozzles                                                        manufacturing of print heads with                                              thousands of nozzles.                                                    Monolithic,                                                                          The nozzle plate is deposited as a                                                             ♦ High accuracy (<1                                                            ♦ Requires sacrificial                                           layer under the   ♦                                                                Silverbrook, EP          surface                                                                              layer using standard VLSI deposition                                                           ♦ Monolithic                                                                   nozzle plate to form the                                                                         0771 658 A2 and          micro-                                                                               techniques. Nozzles are etched in the                                                          ♦ Low cost                                                                     chamber           related patent           machined                                                                             nozzle plate using VLSI lithography                                                            ♦ Existing processes can                                                       ♦ Surface may be                                                 fragile to the touch                                                                             applications             using VLSI                                                                           and etching.    used                            ♦                                                                IJ01, IJ02, IJ04,        lithographic                                          IJ11                     processes                                             ♦                                                                IJ12, IJ17, IJ18,                                                              IJ20                                                                           ♦                                                                IJ22, IJ24, IJ27,                                                              IJ28                                                                           ♦                                                                IJ29, IJ30, IJ31,                                                              IJ32                                                                           ♦                                                                IJ33, IJ34, IJ36,                                                              IJ37                                                                           ♦                                                                IJ38, IJ39, IJ40,                                                              IJ41                                                                           ♦                                                                IJ42, IJ43, IJ44         Monolithic,                                                                          The nozzle plate is a buried etch stop                                                         ♦ High accuracy (<1                                                            ♦ Requires long etch                                             times             ♦                                                                IJ03, IJ05, IJ06,        etched                                                                               in the wafer. Nozzle chambers are                                                              ♦ Monolithic                                                                   ♦ Requires a support                                             wafer             IJ07                     through                                                                              etched in the front of the wafer, and                                                          ♦ Low cost        ♦                                                                IJ08, IJ09, IJ10,        substrate                                                                            the wafer is thinned from the back                                                             ♦ No differential expansion                                                                      IJ13                           side. Nozzles are then etched in the            ♦                                                                IJ14, IJ15, IJ16,              etch stop layer.                                IJ19                                                                           ♦                                                                IJ21, IJ23, IJ25,                                                              IJ26                     No nozzle                                                                            Various methods have been tried to                                                             ♦ No nozzles to become                                                         ♦ Difficult to control                                           drop position     ♦                                                                Ricoh 1995               plate eliminate the nozzles entirely, to                                                             clogged       accurately        Sekiya et al U.S.              prevent nozzle clogging. These                                                                               ♦ Crosstalk                                                                        Pat. No. 5,412,413             include thermal bubble mechanisms               ♦                                                                1993 Hadimioglu                and acoustic lens mechanisms                    et al EUP 550,192                                                              ♦                                                                1993 Elrod et al                                                               EUP 572,220              Trough                                                                               Each drop ejector has a trough                                                                 ♦ Reduced manufacturing                                                        ♦ Drop firing direction                                          is sensitive to   ♦                                                                IJ35                           through which a paddle moves.                                                                  complexity    wicking.                                         There is no nozzle plate.                                                                      ♦ Monolithic                               Nozzle slit                                                                          The elimination of nozzle holes and                                                            ♦ No nozzles to become                                                         ♦ Difficult to control                                           drop position     ♦                                                                1989 Saito et al         instead of                                                                           replacement by a slit encompassing                                                             clogged       accurately        U.S. Pat. No.            individual                                                                           many actuator positions reduces                                                                              ♦ Crosstalk                                                                        4,799,068                nozzles                                                                              nozzle clogging, but increases                                                 crosstalk due to ink surface waves                                       __________________________________________________________________________     DROP EJECTION DIRECTION                                                        Ejection                                                                       direction                                                                            Description     Advantages    Disadvantages     Examples                 __________________________________________________________________________     Edge  Ink flow is along the surface of the                                                           ♦ Simple construction                                                          ♦ Nozzles limited to                                             edge              ♦                                                                Canon Bubblejet          (`edge                                                                               chip, and ink drops are ejected from                                                           ♦ No silicon etching                                                           ♦ High resolution is                                             difficult         1979 Endo et al GB       shooter`)                                                                            the chip edge.  ♦ Good heat sinking                                                            ♦ Fast color printing                                            requires one print                                                                               patent 2,007,162                               substrate     head per color    ♦                                                                Xerox heater-in-                               ♦ Mechanically strong                                                                            pit 1990 Hawkins                                                               et                                             ♦ Ease of chip handing                                                                           al U.S. Pat. No.                                                               4,899,181                                                                      ♦                                                                Tone-jet                 Surface                                                                              Ink flow is along the surface of the                                                           ♦ No bulk silicon etching                                                      ♦ Maximum ink flow is                                            severely          ♦                                                                Hewlett-Packard          (`roof                                                                               chip, and ink drops are ejected from                                                           required      restricted        TIJ 1982 Vaught et       shooter`)                                                                            the chip surface, normal to the plane                                                          ♦ Silicon can make an                                                                            al U.S. Pat. No.               of the chip.    effective heat sink             4,490,728                                      ♦ Mechanical strength                                                                            ♦                                                                IJ02, IJ11, IJ12,                                                              IJ20                                                                           ♦                                                                IJ22                     Through                                                                              Ink flow is through the chip, and ink                                                          ♦ High ink flow                                                                ♦ Requires bulk silicon                                          etching           ♦                                                                Silverbrook, EP          chip, drops are ejected from the front                                                               ♦ Suitable for pagewidth                                                                         0771 658 A2 and          forward (`up                                                                         surface of the chip.                                                                           ♦ High nozzle packing                                                                            related patent           shooter`)             density therefore low           applications                                   manufacturing cost              ♦                                                                IJ04, IJ17, IJ18,                                                              IJ24                                                                           ♦                                                                IJ27-IJ45                Through                                                                              Ink flow is through the chip, and ink                                                          ♦ High ink flow                                                                ♦ Requires wafer                                                 thinning          ♦                                                                IJ01, IJ03, IJ05,        chip, reverse                                                                        drops are ejected from the rear                                                                ♦ Suitable for pagewidth                                                       ♦ Requires special                                               handling during   IJ06                     (`down                                                                               surface of the chip.                                                                           ♦ High nozzle packing                                                          manufacture       ♦                                                                IJ07, IJ08, IJ09,        shooter`)             density therefore low           IJ10                                           manufacturing cost              ♦                                                                IJ13, IJ14, IJ15,                                                              IJ16                                                                           ♦                                                                IJ19, IJ21, IJ23,                                                              IJ25                                                                           ♦                                                                IJ26                     Through                                                                              Ink flow is through the actuator,                                                              ♦ Suitable for piezoelectric                                                   ♦ Pagewidth print heads                                          require several   ♦                                                                Epson Stylus             actuator                                                                             which is not fabricated as part of the                                                         print heads   thousand connections to drive                                                  circuits          ♦                                                                Tektronix hot                  same substrate as the drive   ♦ Cannot be                                                      manufactured ip standard                                                                         melt piezoelectric             transistors.                  CMOS fabs         ink jets                                                     ♦ Complex assembly                                               required                                   __________________________________________________________________________     INK TYPE                                                                       Ink type                                                                             Description     Advantages    Disadvantages     Examples                 __________________________________________________________________________     Aqueous,                                                                             Water based ink which typically                                                                ♦ Environmentally friendly                                                     ♦ Slow                                                                             ♦                                                                Most existing            dye   contains: water, dye, surfactant,                                                              ♦ No odor                                                                      ♦ Corrosive                                                                        inkjets                        humectant, and biocide.       ♦ Bleeds on                                                                        ♦ All                                                            IJ series ink                  Modern ink dyes have high water-                                                                             ♦ May                                                                              jetskethrough                  fastness, light fastness      ♦ Cockles                                                                          ♦                                                                Silverbrook, EP                                                                0771 658 A2 and                                                                related patent                                                                 applications             Aqueous,                                                                             Water based ink which typically                                                                , Environmentally friendly                                                                   ♦ Slow                                                                             ♦                                                                IJ02, IJ04, IJ21,        pigment                                                                              contains: water, pigment, surfactant,                                                          ♦ No odor                                                                      ♦ Corrosive                                                                        IJ26                           humectant, and biocide.                                                                        ♦ Reduced bleed                                                                ♦ Pigment may clog                                               nozzles           ♦                                                                IJ27, IJ30                     Pigments have an advantage in                                                                  ♦ Reduced wicking                                                              ♦ Pigment may clog                                               actuator          ♦                                                                Silverbrook, EP                reduced bleed, wicking and                                                                     ♦ Reduced strikethrough                                                        mechanisms        0771 658 A2 and                strikethrough.                ♦ Cockles                                                                          related patent                                                                 applications                                                                   ♦                                                                Piezoelectric                                                                  ink-jets                                                                       ♦                                                                Thermal ink jets                                                               (with significant                                                              restrictions)            Methyl Ethyl                                                                         MEK is a highly volatile solvent                                                               ♦ Very fast drying                                                             ♦ Odorous                                                                          ♦ All                                                            IJ series ink            Ketone                                                                               used for industrial printing on                                                                ♦ Prints on various                                                            ♦ Flammable                                                                        jets                     (MEK) difficult surfaces such as aluminum                                                            such as metals and plastics                                    cans.                                                                    Alcohol                                                                              Alcohol based inks can be used                                                                 ♦ Fast drying                                                                  ♦ Slight                                                                           ♦ All                                                            IJ series ink            (ethanol, 2-                                                                         where the printer must operate at                                                              ♦ Operates at sub-freezing                                                     ♦ Flammable                                                                        jets                     butanol, and                                                                         temperatures below the freezing                                                                temperatures                                             others)                                                                              point of water. An example of this is                                                          ♦ Reduced paper cockle                           in-camera consumer photographic                                                                ♦ Low cost                                       printing.                                                                Phase The ink is solid at room temperature,                                                          ♦ No drying time- ink                                                          ♦ High                                                                             ♦                                                                Tektronix hot            change                                                                               and is melted in the print head before                                                         instantly freezes on the                                                                     ♦ Printed ink typically                                          has a `waxy` feel melt piezoelectric       (hot melt)                                                                           jetting. Hot melt inks are usually                                                             print medium  ♦ Printed pages may                                              `block`           ink jets                       wax based, with a melting point                                                                ♦ Almost any print medium                                                      ♦ Ink temperature may                                            be above the      ♦                                                                1989 Nowak U.S.                around 80° C. After jetting the ink                                                     can be used   curie point of permanent                                                                         Pat. No. 4,820,346             freezes almost instantly upon                                                                  ♦ No paper cockle occurs                                                       ♦ Ink heaters consume                                            power             ♦ All                                                            IJ series ink                  contacting the print medium or a                                                               ♦ No wicking occurs                                                            ♦ Long warm-up                                                                     jets                           transfer roller.                                                                               ♦ No bleed occurs                                                ♦ No strikethrough occurs                  Oil   Oil based inks are extensively used                                                            ♦ High solubility medium                                                       ♦ High viscosity: this                                           is a significant  ♦ All                                                            IJ series ink                  in offset printing. They have                                                                  some dyes     limitation for use in inkjets,                                                                   jetsh                          advantages in improved                                                                         ♦ Does not cockle paper                                                        usually require a low viscosity. Some            characteristics on paper (especially                                                           ♦ Does not wick through                                                        short chain and multi-branched oils              no wicking or cockle). Oil soluble                                                             paper         have a sufficiently low viscosity.               dies and pigments are required.                                                                              ♦ Slow drying                Micro-                                                                               A microemulsion is a stable, self                                                              ♦ Stops ink bleed                                                              ♦ Viscosity higher than                                          water             ♦ All                                                            IJ series                emulsion                                                                             forming emulsion of oil, water, and                                                            ♦ High dye solubility                                                          ♦ Cost is slightly                                               higher than water based                                                                          inkjets                        surfactant. The characteristic drop                                                            ♦ Water, oil, and amphiphilic                                                  ink                                              size is less than 100 nm, and is                                                               soluble dies can be used                                                                     ♦ High surfactant                                                concentration required                           determined by the preferred                                                                    ♦ Can stabilize pigment                                                        (around 5%)                                      curvature of the surfactant.                                                                   suspensions                                              __________________________________________________________________________

    ______________________________________                                         Australian                                                                     Provisional                                                                    Number  Filing Date                                                                              Title                                                        ______________________________________                                         PO7935  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM01)                                   PO7936  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM02)                                   PO7937  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM03)                                   PO8061  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM04)                                   PO8054  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM05)                                   PO8065  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM06)                                   PO8055  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM07)                                   PO8053  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM08)                                   PO8078  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM09)                                   PO7933  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM10)                                   PO7950  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM11)                                   PO7949  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM12)                                   PO8060  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM13)                                   PO8059  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM14)                                   PO8073  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM15)                                   PO8076  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM16)                                   PO8075  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM17)                                   PO8079  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM18)                                   PO8050  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM19)                                   PO8052  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM20)                                   PO7948  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM21)                                   PO7951  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM22)                                   PO8074  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM23)                                   PO7941  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM24)                                   PO8077  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM25)                                   PO8058  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM26)                                   PO8051  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM27)                                   PO8045  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM28)                                   PO7952  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM29)                                   PO8046  15-Jul-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM30)                                   PO8503  11-Aug-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM30a)                                  PO9390  23-Sep-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM31)                                   PO9392  23-Sep-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM32)                                   PP0889  12-Dec-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM35)                                   PP0887  12-Dec-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM36)                                   PP0882  12-Dec-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM37)                                   PP0874  12-Dec-97 A Method of Manufacture of an Image                                            Creation Apparatus (IJM38)                                   PP1396  19-Jan-98 A Method of Manufacture of an Image                                            Creation Apparatus (IJM39)                                   PP2591  25-Mar-98 A Method of Manufacture of an Image                                            Creation Apparatus (IJM41)                                   PP3989  9-Jun-98  A Method of Manufacture of an Image                                            Creation Apparatus (IJM40)                                   PP3990  9-Jun-98  A Method of Manufacture of an Image                                            Creation Apparatus (IJM42)                                   PP3986  9-Jun-98  A Method of Manufacture of an Image                                            Creation Apparatus (IJM43)                                   PP3984  9-Jun-98  A Method of Manufacture of an Image                                            Creation Apparatus (IJM44)                                   PP3982  9-Jun-98  A Method of Manufacture of an Image                                            Creation Apparatus (IJM45)                                   PO8003  15-Jul-97 Supply Method and Apparatus (F1)                             PO8005  15-Jul-97 Supply Method and Apparatus (F2)                             PO9404  23-Sep-97 A Device and Method (F3)                                     PO7943  15-Jul-97 A device (MEMS01)                                            PO8006  15-Jul-97 A device (MEMS02)                                            PO8007  15-Jul-97 A device (MEMS03)                                            PO8008  15-Jul-97 A device (MEMS04)                                            PO8010  15-Jul-97 A device (MEMS05)                                            PO8011  15-Jul-97 A device (MEMS06)                                            PO7947  15-Jul-97 A device (MEMS07)                                            PO7945  15-Jul-97 A device (MEMS08)                                            PO7944  15-Jul-97 A device (MEMS09)                                            PO7946  15-Jul-97 A device (MEMS10)                                            PO9393  23-Sep-97 A Device and Method (MEMS11)                                 PP0875  12-Dec-97 A Device (MEMS12)                                            PP0894  12-Dec-97 A Device and Method (MEMS13)                                 PP0895  12-Dec-97 An Image Creation Method and Apparatus                                         (IR01)                                                       PP0870  12-Dec-97 A Device and Method (IR02)                                   PP0869  12-Dec-97 A Device and Method (IR04)                                   PP0887  12-Dec-97 Image Creation Method and Apparatus                                            (IR05)                                                       PP0885  12-Dec-97 An Image Production System (IR06)                            PP0884  12-Dec-97 Image Creation Method and Apparatus                                            (IR10)                                                       PP0886  12-Dec-97 Image Creation Method and Apparatus                                            (IR12)                                                       PP0871  12-Dec-97 A Device and Method (IR13)                                   PP0876  12-Dec-97 An Image Processing Method and Apparatus                                       (IR14)                                                       PP0877  12-Dec-97 A Device and Method (IR16)                                   PP0878  12-Dec-97 A Device and Method (IR17)                                   PP0879  12-Dec-97 A Device and Method (IR18)                                   PP0883  12-Dec-97 A Device and Method (IR19)                                   PP0880  12-Dec-97 A Device and Method (IR20)                                   PP0881  12-Dec-97 A Device and Method (IR21)                                   PP2370  16-Mar-98 Data Processing Method and Apparatus                                           (Dot01)                                                      PP2371  16-Mar-98 Data Processing Method and Apparatus                                           (Dot02)                                                      PO7991  15-Jul-97 Image Processing Method and Apparatus                                          (ART01)                                                      PO8505  11-Aug-97 Image Processing Method and Apparatus                                          (ART01a)                                                     PO7988  15-Jul-97 Image Processing Method and Apparatus                                          (ART02)                                                      PO7993  15-Jul-97 Image Processing Method and Apparatus                                          (ART03)                                                      PO8012  15-Jul-97 Image Processing Method and Apparatus                                          (ART05)                                                      PO8017  15-Jul-97 Image Processing Method and Apparatus                                          (ART06)                                                      PO8014  15-Jul-97 Media Device (ART07)                                         PO8025  15-Jul-97 Image Processing Method and Apparatus                                          (ART08)                                                      PO8032  15-Jul-97 Image Processing Method and Apparatus                                          (ART09)                                                      PO7999  15-Jul-97 Image Processing Method and Apparatus                                          (ART10)                                                      PO7998  15-Jul-97 Image Processing Method and Apparatus                                          (ART11)                                                      PO8031  15-Jul-97 Image Processing Method and Apparatus                                          (ART12)                                                      PO8030  15-Jul-97 Media Device (ART13)                                         PO8498  11-Aug-97 Image Processing Method and Apparatus                                          (ART14)                                                      PO7997  15-Jul-97 Media Device (ART15)                                         PO7979  15-Jul-97 Media Device (ART16)                                         PO8015  15-Jul-97 Media Device (ART17)                                         PO7978  15-Jul-97 Media Device (ART18)                                         PO7982  15-Jul-97 Data Processing Method and Apparatus                                           (ART19)                                                      PO7989  15-Jul-97 Data Processing Method and Apparatus                                           (ART20)                                                      PO8019  15-Jul-97 Media Processing Method and Apparatus                                          (ART21)                                                      PO7980  15-Jul-97 Image Processing Method and Apparatus                                          (ART22)                                                      PO7942  15-Jul-97 Image Processing Method and Apparatus                                          (ART23)                                                      PO8018  15-Jul-97 Image Processing Method and Apparatus                                          (ART24)                                                      PO7938  15-Jul-97 Image Processing Method and Apparatus                                          (ART25)                                                      PO8016  15-Jul-97 Image Processing Method and Apparatus                                          (ART26)                                                      PO8024  15-Jul-97 Image Processing Method and Apparatus                                          (ART27)                                                      PO7940  15-Jul-97 Data Processing Method and Apparatus                                           (ART28)                                                      PO7939  15-Jul-97 Data Processing Method and Apparatus                                           (ART29)                                                      PO8501  11-Aug-97 Image Processing Method and Apparatus                                          (ART30)                                                      PO8500  11-Aug-97 Image Processing Method and Apparatus                                          (ART31)                                                      PO7987  15-Jul-97 Data Processing Method and Apparatus                                           (ART32)                                                      PO8022  15-Jul-97 Image Processing Method and Apparatus                                          (ART33)                                                      PO8497  11-Aug-97 Image Processing Method and Apparatus                                          (ART30)                                                      PO8029  15-Jul-97 Sensor Creation Method and Apparatus                                           (ART36)                                                      PO7985  15-Jul-97 Data Processing Method and Apparatus                                           (ART37)                                                      PO8020  15-Jul-97 Data Processing Method and Apparatus                                           (ART38)                                                      PO8023  15-Jul-97 Data Processing Method and Apparatus                                           (ART39)                                                      PO9395  23-Sep-97 Data Processing Method and Apparatus                                           (ART4)                                                       PO8021  15-Jul-97 Data Processing Method and Apparatus                                           (ART40)                                                      PO8504  11-Aug-97 Image Processing Method and Apparatus                                          (ART42)                                                      PO8000  15-Jul-97 Data Processing Method and Apparatus                                           (ART43)                                                      PO7977  15-Jul-97 Data Processing Method and Apparatus                                           (ART44)                                                      PO7934  15-Jul-97 Data Processing Method and Apparatus                                           (ART45)                                                      PO7990  15-Jul-97 Data Processing Method and Apparatus                                           (ART46)                                                      PO8499  11-Aug-97 Image Processing Method and Apparatus                                          (ART47)                                                      PO8502  11-Aug-97 Image Processing Method and Apparatus                                          (ART48)                                                      PO7981  15-Jul-97 Data Processing Method and Apparatus                                           (ART50)                                                      PO7986  15-Jul-97 Data Processing Method and Apparatus                                           (ART51)                                                      PO7983  15-Jul-97 Data Processing Method and Apparatus                                           (ART52)                                                      PO8026  15-Jul-97 Image Processing Method and Apparatus                                          (ART53)                                                      PO8027  15-Jul-97 Image Processing Method and Apparatus                                          (ART54)                                                      PO8028  15-Jul-97-                                                                               Image Processing Method and Apparatus                                          (ART56)                                                      PO9394  23-Sep-97 Image Processing Method and Apparatus                                          (ART57)                                                      PO9396  23-Sep-97 Data Processing Method and Apparatus                                           (ART58)                                                      PO9397  23-Sep-97 Data Processing Method and Apparatus                                           (ART59)                                                      PO9398  23-Sep-97 Pata Processing Method and Apparatus                                           (ART60)                                                      PO9399  23-Sep-97 Data Processing Method and Apparatus                                           (ART61)                                                      PO9400  23-Sep-97 Data Processing Method and Apparatus                                           (ART62)                                                      PO9401  23-Sep-97 Data Processing Method and Apparatus                                           (ART63)                                                      PO9402  23-Sep-97 Data Processing Method and Apparatus                                           (ART64)                                                      PO9403  23-Sep-97 Data Processing Method and Apparatus                                           (ART65)                                                      PO9405  23-Sep-97 Data Processing Method and Apparatus                                           (ART66)                                                      PPO959  16-Dec-97 A Data Processing Method and Apparatus                                         (ART68)                                                      PP1397  19-Jan-98 A Media Device (ART69)                                       ______________________________________                                     

We claim:
 1. A method of manufacturing an ink jet printhead which includes:providing a substrate; depositing a doped layer on the substrate and etching said layer to create an array of nozzles on the substrate with a nozzle chamber in communication with each nozzle; and utilizing planar monolithic deposition, lithographic and etching processes to create a paddle arranged in each nozzle chamber each paddle being pivotally arranged relative to the nozzle and having a current-carrying device therein so that when a magnetic field is applied to the paddle, a lorenz force is exerted on the paddle to cause pivoting of the paddle and ejection of ink from the nozzle.
 2. A method of manufacturing an ink jet printhead as claimed in claim 1 wherein multiple ink jet printheads are formed simultaneously on the substrate.
 3. A method of manufacturing an ink jet printhead as claimed in claim 1 wherein said substrate is a silicon wafer.
 4. A method of manufacturing an ink jet printhead as claimed in claim 1 wherein integrated drive electronics are formed on the same substrate.
 5. A method of manufacturing an ink jet printhead as claimed in claim 4 wherein said integrated drive electronics are formed using a CMOS fabrication process.
 6. A method of manufacturing an ink jet printhead as claimed in claim 1 wherein ink is ejected from said substrate normal to said substrate.
 7. A method of manufacture of an ink jet printhead arrangement including a series of nozzle chambers, said method comprising the steps of:(a) utilising an initial semiconductor wafer having an electrical circuitry layer and a buried epitaxial layer formed thereon, in addition to a top protecting layer having a series of vias interconnected to predetermined portions of said circuitry layer; (b) forming on said semiconductor wafer layer a first conductive layer including a first conductive coil interconnected to predetermined portions of said circuitry layer; (c) depositing and etching, on said first conductive layer, a non-conductive layer including predetermined vias for the interconnection of subsequent layers with lower layers; (d) forming a second conductive layer on said non-conductive layer, including a second conductive coil and the interconnection of predetermined portions of said coil with said first conductive coil and said circuitry layer; (e) depositing and etching a second non-conductive layer over said second conductive layer said etching including etching a series of slots in said second non-conductive layer; (f) etching a series of slots through said first and second non-conductive layer and said first and second conductive layers so as to define a nozzle paddle; (g) etching said semiconductor wafer under said nozzle paddle so as to define a nozzle chamber; (h) back etching said semiconductor wafer to said epitaxial layer; and (i) etching said epitaxial layer to define a nozzle ejection hole therein interconnecting with said nozzle chamber.
 8. A method as claimed in claim 7 wherein said step (g) utilizes said epitaxial layer as an etch stop.
 9. A method as claimed in claim 7 wherein said step (g) comprises a crystallographic etch.
 10. A method as claimed in claim 7 wherein said step (i) includes etching a series of small holes in a wall of said nozzle chamber interconnecting said chamber with the ambient atmosphere.
 11. A method as claimed in claim 7 wherein said first conductive layer and said second conductive layer are formed from substantially copper.
 12. A method as claimed in claim 7 further including the step of depositing corrosion barriers over portions of said arrangement so as to reduce corrosion effects.
 13. A method as claimed in claim 7 wherein said wafer comprises a double side polished CMOS wafer.
 14. A method as claimed in claim 7 wherein step (i) is also utilized to simultaneously separate said wafer into separate printheads. 